[improve](testcase) Increase utcase and itcase

[JNSimba]

Proposed changes

Issue Number: close #xxx

Problem Summary:

1. Increase case coverage
2. Standardize some classes and add public annotations
3. Add cases in abnormal situations, such as JM TM restart, etc.

Checklist(Required)

1. Does it affect the original behavior: (Yes/No/I Don't know)
2. Has unit tests been added: (Yes/No/No Need)
3. Has document been added or modified: (Yes/No/No Need)
4. Does it need to update dependencies: (Yes/No)
5. Are there any changes that cannot be rolled back: (Yes/No)

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...