check duplicate exclusion cases in ProblemList files

[sophia-guo]

If there are more exclusion entries for same testcase only the last occurrence takes effects even if each entry has different tracked issue or different os-arch.

Testcase excluded by multiple lines happened quite a few times which causes confusion and wastes efforts to triage.

We should check ProblemList files for this to ensure no multiple entries is added, especially when PR is adding the new entry.

The main script for problemlist check is https://github.com/adoptium/aqa-tests/blob/master/scripts/disabled_tests/exclude_parser.py

#5863 (comment)