DATA RACE in the TestGlobalMemoryControlForAnalyze

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

### 2. What did you expect to see? (Required)

### 3. What did you see instead (Required)
```
==================
WARNING: DATA RACE
Write at 0x00c020ef9de0 by goroutine 911520:
github.com/pingcap/tidb/executor.ResetContextOfStmt()
executor/executor.go:2052 +0x824
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2142 +0x39c
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).Exec()
testkit/testkit.go:294 +0x4db
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3094 +0x49f
github.com/pingcap/failpoint.(*Failpoint).Enable()
external/com_github_pingcap_failpoint/failpoint.go:54 +0x44
github.com/pingcap/failpoint.(*Failpoints).Enable()
external/com_github_pingcap_failpoint/failpoints.go:105 +0x276
github.com/pingcap/failpoint.Enable()
external/com_github_pingcap_failpoint/failpoints.go:222 +0x435
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3089 +0x436
github.com/pingcap/failpoint.(*Failpoint).Enable()
external/com_github_pingcap_failpoint/failpoint.go:54 +0x44
github.com/pingcap/failpoint.(*Failpoints).Enable()
external/com_github_pingcap_failpoint/failpoints.go:105 +0x276
github.com/pingcap/failpoint.Enable()
external/com_github_pingcap_failpoint/failpoints.go:222 +0x3ef
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3088 +0x3f0
github.com/pingcap/tidb/executor.(*ExecStmt).handleNoDelay()
executor/adapter.go:779 +0x34a
github.com/pingcap/tidb/executor.(*ExecStmt).Exec()
executor/adapter.go:574 +0x1299
github.com/pingcap/tidb/session.runStmt()
session/session.go:2351 +0x761
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2215 +0xfa5
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).MustExecWithContext()
testkit/testkit.go:130 +0xb7
github.com/pingcap/tidb/testkit.(*TestKit).MustExec()
testkit/testkit.go:125 +0xf7
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3073 +0xda
github.com/pingcap/tidb/sessionctx/variable.glob..func168()
sessionctx/variable/sysvar.go:882 +0x5e
github.com/pingcap/tidb/sessionctx/variable.(*SysVar).Validate()
sessionctx/variable/variable.go:301 +0x12f
github.com/pingcap/tidb/session.(*session).SetGlobalSysVar()
session/session.go:1493 +0xe4
github.com/pingcap/tidb/executor.(*SetExecutor).setSysVariable()
executor/set.go:149 +0x6cd
github.com/pingcap/tidb/executor.(*SetExecutor).Next()
executor/set.go:99 +0xf59
github.com/pingcap/tidb/executor.Next()
executor/executor.go:328 +0x5c3
github.com/pingcap/tidb/executor.(*ExecStmt).next()
executor/adapter.go:1198 +0x89
github.com/pingcap/tidb/executor.(*ExecStmt).handleNoDelayExecutor()
executor/adapter.go:950 +0x6f1
github.com/pingcap/tidb/executor.(*ExecStmt).handleNoDelay()
executor/adapter.go:779 +0x34a
github.com/pingcap/tidb/executor.(*ExecStmt).Exec()
executor/adapter.go:574 +0x1299
github.com/pingcap/tidb/session.runStmt()
session/session.go:2351 +0x761
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2215 +0xfa5
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).MustExecWithContext()
testkit/testkit.go:130 +0xb7
github.com/pingcap/tidb/testkit.(*TestKit).MustExec()
testkit/testkit.go:125 +0xf7
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3072 +0xba
github.com/pingcap/tidb/session.runStmt()
session/session.go:2351 +0x761
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2215 +0xfa5
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).MustExecWithContext()
testkit/testkit.go:130 +0xb7
github.com/pingcap/tidb/testkit.(*TestKit).MustExec()
testkit/testkit.go:125 +0xf7
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3071 +0x9a
github.com/pingcap/tidb/domain.(*Domain).rebuildSysVarCache()
domain/sysvar_cache.go:146 +0x844
github.com/pingcap/tidb/domain.(*Domain).LoadSysVarCacheLoop()
domain/domain.go:1384 +0xa8
github.com/pingcap/tidb/session.BootstrapSession()
session/session.go:3337 +0x693
github.com/pingcap/tidb/domain.(*Domain).GetSessionCache()
domain/sysvar_cache.go:62 +0x59
github.com/pingcap/tidb/session.(*session).loadCommonGlobalVariablesIfNeeded()
session/session.go:3656 +0x104
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2134 +0x2a5
github.com/pingcap/tidb/session.(*session).ExecuteInternal()
session/session.go:1668 +0x471
github.com/pingcap/tidb/domain.(*Domain).LoadPrivilegeLoop()
domain/domain.go:1328 +0x130
github.com/pingcap/tidb/session.BootstrapSession()
session/session.go:3330 +0x644
github.com/pingcap/tidb/testkit.bootstrap()
testkit/mockstore.go:85 +0xac
github.com/pingcap/tidb/testkit.CreateMockStoreAndDomain()
testkit/mockstore.go:70 +0xe9
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3068 +0x55
testing.tRunner()
GOROOT/src/testing/testing.go:1446 +0x216
testing.(*T).Run.func1()
GOROOT/src/testing/testing.go:1493 +0x47
Previous read at 0x00c020ef9de0 by goroutine 924724:
github.com/pingcap/tidb/util/servermemorylimit.killSessIfNeeded()
util/servermemorylimit/servermemorylimit.go:125 +0x2a7
github.com/pingcap/tidb/util/servermemorylimit.(*Handle).Run()
util/servermemorylimit/servermemorylimit.go:74 +0x148
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze.func2()
executor/analyzetest/analyze_test.go:3079 +0x39
Goroutine 911520 (running) created at:
testing.(*T).Run()
GOROOT/src/testing/testing.go:1493 +0x75d
testing.runTests.func1()
GOROOT/src/testing/testing.go:1846 +0x99
testing.tRunner()
GOROOT/src/testing/testing.go:1446 +0x216
testing.runTests()
GOROOT/src/testing/testing.go:1844 +0x7ec
testing.(*M).Run()
GOROOT/src/testing/testing.go:1726 +0xa84
go.uber.org/goleak.VerifyTestMain()
external/org_uber_go_goleak/testmain.go:53 +0x70
executor/analyzetest/analyzetest_test.TestMain()
executor/analyzetest/main_test.go:29 +0x318
main.main()
bazel-out/k8-fastbuild/bin/executor/analyzetest/analyzetest_test_/testmain.go:212 +0x5e8
Goroutine 924724 (running) created at:
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3079 +0x331
github.com/pingcap/tidb/executor.(*ExecStmt).handleNoDelay()
executor/adapter.go:779 +0x34a
github.com/pingcap/tidb/executor.(*ExecStmt).Exec()
executor/adapter.go:574 +0x1299
github.com/pingcap/tidb/session.runStmt()
session/session.go:2351 +0x761
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2215 +0xfa5
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).MustExecWithContext()
testkit/testkit.go:130 +0xb7
github.com/pingcap/tidb/testkit.(*TestKit).MustExec()
testkit/testkit.go:125 +0xf7
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3073 +0xda
github.com/pingcap/tidb/sessionctx/variable.glob..func168()
sessionctx/variable/sysvar.go:882 +0x5e
github.com/pingcap/tidb/sessionctx/variable.(*SysVar).Validate()
sessionctx/variable/variable.go:301 +0x12f
github.com/pingcap/tidb/session.(*session).SetGlobalSysVar()
session/session.go:1493 +0xe4
github.com/pingcap/tidb/executor.(*SetExecutor).setSysVariable()
executor/set.go:149 +0x6cd
github.com/pingcap/tidb/executor.(*SetExecutor).Next()
executor/set.go:99 +0xf59
github.com/pingcap/tidb/executor.Next()
executor/executor.go:328 +0x5c3
github.com/pingcap/tidb/executor.(*ExecStmt).next()
executor/adapter.go:1198 +0x89
github.com/pingcap/tidb/executor.(*ExecStmt).handleNoDelayExecutor()
executor/adapter.go:950 +0x6f1
github.com/pingcap/tidb/executor.(*ExecStmt).handleNoDelay()
executor/adapter.go:779 +0x34a
github.com/pingcap/tidb/executor.(*ExecStmt).Exec()
executor/adapter.go:574 +0x1299
github.com/pingcap/tidb/session.runStmt()
session/session.go:2351 +0x761
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2215 +0xfa5
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).MustExecWithContext()
testkit/testkit.go:130 +0xb7
github.com/pingcap/tidb/testkit.(*TestKit).MustExec()
testkit/testkit.go:125 +0xf7
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3072 +0xba
github.com/pingcap/tidb/session.runStmt()
session/session.go:2351 +0x761
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2215 +0xfa5
github.com/pingcap/tidb/testkit.(*TestKit).ExecWithContext()
testkit/testkit.go:321 +0x96e
github.com/pingcap/tidb/testkit.(*TestKit).MustExecWithContext()
testkit/testkit.go:130 +0xb7
github.com/pingcap/tidb/testkit.(*TestKit).MustExec()
testkit/testkit.go:125 +0xf7
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3071 +0x9a
github.com/pingcap/tidb/domain.(*Domain).rebuildSysVarCache()
domain/sysvar_cache.go:146 +0x844
github.com/pingcap/tidb/domain.(*Domain).LoadSysVarCacheLoop()
domain/domain.go:1384 +0xa8
github.com/pingcap/tidb/session.BootstrapSession()
session/session.go:3337 +0x693
github.com/pingcap/tidb/domain.(*Domain).GetSessionCache()
domain/sysvar_cache.go:62 +0x59
github.com/pingcap/tidb/session.(*session).loadCommonGlobalVariablesIfNeeded()
session/session.go:3656 +0x104
github.com/pingcap/tidb/session.(*session).ExecuteStmt()
session/session.go:2134 +0x2a5
github.com/pingcap/tidb/session.(*session).ExecuteInternal()
session/session.go:1668 +0x471
github.com/pingcap/tidb/domain.(*Domain).LoadPrivilegeLoop()
domain/domain.go:1328 +0x130
github.com/pingcap/tidb/session.BootstrapSession()
session/session.go:3330 +0x644
github.com/pingcap/tidb/testkit.bootstrap()
testkit/mockstore.go:85 +0xac
github.com/pingcap/tidb/testkit.CreateMockStoreAndDomain()
testkit/mockstore.go:70 +0xe9
executor/analyzetest/analyzetest_test.TestGlobalMemoryControlForAnalyze()
executor/analyzetest/analyze_test.go:3068 +0x55
testing.tRunner()
GOROOT/src/testing/testing.go:1446 +0x216
testing.(*T).Run.func1()
GOROOT/src/testing/testing.go:1493 +0x47
==================
```
### 4. What is your TiDB version? (Required)