[Bug]: CI UT timeout failures in transaction abort and backup protection tests

### Is there an existing issue for the same bug?

- [x] I have checked the existing issues. `TestSpeedupAbortAllTxn` previously failed in #22781, but the two backup protection failures have no matching issue.

### Branch Name

`issue-25421-main` (PR #25872)

### Commit ID

`abc51d49eeffbaccc136026dfa57fd874a29f73b`

### Other Environment Information

```Markdown
- Hardware parameters: GitHub Actions runner, memory cgroup limit about 14 GiB
- OS type: Ubuntu/x86
- Others: MatrixOne ALL CI, pull_request_target
```

### Actual Behavior

The Ubuntu/x86 UT job failed with three timeout-related test failures:

1. `TestSpeedupAbortAllTxn` failed after 14.10s because connecting to `127.0.0.1:14220` timed out and the test received `rpc timeout`.
2. `TestBackupProtectionCheckpointProtection` failed because force flush exceeded its 5s deadline; no checkpoint was produced.
3. `TestBackupProtectionMetadataFileFiltering` failed because forced incremental checkpoint execution exceeded its 5s deadline.

The same workflow also reported severe runner memory pressure: the coverage process was OOM-killed at approximately 14 GiB cgroup usage. The failures are outside the files changed by PR #25872 and appear to be CI/test instability under resource contention.

Failed job: https://github.com/matrixorigin/matrixone/actions/runs/29845560764/job/88685358748

Related historical recurrence: #22781

### Expected Behavior

The UT suite should tolerate expected CI runner contention and complete without RPC or checkpoint deadline failures.

### Steps to Reproduce

```Markdown
1. Trigger MatrixOne ALL CI for PR #25872 at commit abc51d49eeffbaccc136026dfa57fd874a29f73b.
2. Run the Ubuntu/x86 Unit Testing job.
3. Observe the three timeout failures in the UT report.
```

### Additional information

Failure signatures:

```text
TestSpeedupAbortAllTxn: rpc timeout
TestBackupProtectionCheckpointProtection: force flush failed: context deadline exceeded
TestBackupProtectionMetadataFileFiltering: context deadline exceeded
FAIL_UT_CASES=TestSpeedupAbortAllTxn,TestBackupProtectionCheckpointProtection,TestBackupProtectionMetadataFileFiltering
```