[Bug]: Ubuntu UT hard timeout leaves engine tests active

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

- [x] I searched open and closed MatrixOne issues for `TestCCPRCreateDelete`, `TestExecuteIteration1`, and `UT HARD TIMEOUT`; no matching issue was found.

### Branch Name

PR #28641 branch `agent/issue-28639-94d7deef`

### Commit ID

`c30779e51a4f60b5ffd88ded72be1289f80fbff3`

### Other Environment Information

- GitHub Actions MatrixOne ALL CI run: https://github.com/matrixorigin/matrixone/actions/runs/34491898016
- Failed job: https://github.com/matrixorigin/matrixone/actions/runs/34491898016/job/102920980615
- Ubuntu/x86 UT execution, attempt 1

### Actual Behavior

The UT job hit its 70-minute hard deadline (wall time: 72m2.885s) and `make ut` exited with error 124. Its post-timeout report identified two still-active cases:

```text
package=github.com/matrixorigin/matrixone/pkg/vm/engine/test test=TestCCPRCreateDelete state=run
package=github.com/matrixorigin/matrixone/pkg/vm/engine/test test=TestExecuteIteration1 state=run
```

No failing assertion or stack trace was emitted before the outer timeout. The triggering PR changes planner/compiler/protobuf/index test files only; it does not modify `pkg/vm/engine/test` or UT orchestration.

### Expected Behavior

The Ubuntu/x86 UT job should complete within its configured deadline, or report a deterministic failure from the engine test rather than leaving active tests until the outer timeout.

### Steps to Reproduce

```Markdown
1. Run the MatrixOne ALL CI Ubuntu/x86 UT job for the referenced commit.
2. Allow the package suite to run through the 70-minute hard deadline.
3. Inspect the active-case report emitted by `run_tests`; it lists `TestCCPRCreateDelete` and `TestExecuteIteration1` as still running.
```

### Additional information

The precise timeout evidence is in the failed job log at the URL above, at approximately `2026-09-10T16:10:41Z`. This issue was discovered while validating #28641 and is unrelated to its regular index-hint change.