[Umbrella] Subissue Improve utils.* test coverage

### Search before asking

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

### Description

Currently, we ignore a lot of classes to make the code coverage pass. We need to add unit tests or integration tests around those classes to improve the coverage.
In this issue, it aims to cover com.alibaba.fluss.utils.* to increase the coverage.

### Willingness to contribute

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

Start by inspecting the com.alibaba.fluss.utils.* classes currently excluded from coverage and identify the missing unit or integration-test entry points. Run the existing coverage checks to establish the baseline, then add tests for the selected utility classes and verify that coverage improves without exclusions.

Written by the indexing model from the issue text.