Print and upload stacktraces before test is timeout

### Search before asking

- [x] I searched in the [issues](https://github.com/alibaba/fluss/issues) and found nothing similar.

### Description

Some recent CI builds[1][2] are still timing out during Flink tests, and it's difficult to determine where the job is getting stuck. I think we should leverage jstack to help identify the root cause.

We can take inspiration from how Flink captures and uploads thread dumps during test failures. For reference, see:
[uploading_watchdog.sh](https://github.com/apache/flink/blob/85edd784fc72c1784849e2b122cbf3215f89817c/tools/azure-pipelines/uploading_watchdog.sh#L76)

[1] https://github.com/alibaba/fluss/actions/runs/15505803078/job/43660438544
[2] https://github.com/alibaba/fluss/actions/runs/15505590729/job/43659968345

### Willingness to contribute

- [ ] I'm willing to submit a PR!