`TestResourceManagerClientTestSuite` is flaky

## Flaky Test

### Which jobs are failing

```
testutil.go:63:
Error Trace: /home/runner/work/pd/pd/pkg/utils/testutil/testutil.go:63
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:972
Error: Condition never satisfied
Test: TestResourceManagerClientTestSuite/TestBasicResourceGroupCURD
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/pkg/utils/testutil/testutil.go:63
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:972
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestBasicResourceGroupCURD
=== RUN TestResourceManagerClientTestSuite/TestLoadRequestUnitConfig
resource_manager_test.go:1081:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:1081
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestLoadRequestUnitConfig
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:1081
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestLoadRequestUnitConfig
=== RUN TestResourceManagerClientTestSuite/TestRemoveStaleResourceGroup
resource_manager_test.go:1120:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:1120
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestRemoveStaleResourceGroup
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:1120
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestRemoveStaleResourceGroup
=== RUN TestResourceManagerClientTestSuite/TestResourceGroupController
resource_manager_test.go:349:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:349
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourceGroupController
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:349
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourceGroupController
=== RUN TestResourceManagerClientTestSuite/TestResourceManagerClientDegradedMode
resource_manager_test.go:1036:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:1036
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourceManagerClientDegradedMode
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:1036
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourceManagerClientDegradedMode
=== RUN TestResourceManagerClientTestSuite/TestResourceManagerClientFailover
resource_manager_test.go:997:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:997
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourceManagerClientFailover
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:997
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourceManagerClientFailover
=== RUN TestResourceManagerClientTestSuite/TestResourcePenalty
resource_manager_test.go:559:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:559
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourcePenalty
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:559
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestResourcePenalty
=== RUN TestResourceManagerClientTestSuite/TestSwitchBurst
resource_manager_test.go:429:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:429
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestSwitchBurst
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:429
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestSwitchBurst
=== RUN TestResourceManagerClientTestSuite/TestWatchResourceGroup
resource_manager_test.go:198:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:198
Error: Received unexpected error:
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestWatchResourceGroup
resource_manager_test.go:159:
Error Trace: /home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:159
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:153
/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.8.2/suite/suite.go:179
/opt/hostedtoolcache/go/1.20.1/x64/src/runtime/panic.go:540
/opt/hostedtoolcache/go/1.20.1/x64/src/testing/testing.go:980
/home/runner/work/pd/pd/tests/integrations/mcs/resourcemanager/resource_manager_test.go:198
Error: Received unexpected error:
[PD:client:ErrClientListResourceGroup]get all resource group failed, rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:43523: connect: connection refused"
Test: TestResourceManagerClientTestSuite/TestWatchResourceGroup
```

### CI link

https://github.com/tikv/pd/actions/runs/5541739628/jobs/10115540475?pr=6799

### Reason for failure (if possible)

### Anything else