refactor: cleanup CombSort

[alxkm]

Cleanup CombSort class, removing redundant code.

Improve code readability.

Removing redundant useless comments.

Refactoring test to common sort approach, it has more tests and will improve code coverage.

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.52%. Comparing base (5113101) to head (5b2b68a).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5303      +/-   ##
============================================
+ Coverage     41.47%   41.52%   +0.05%     
  Complexity     2556     2556              
============================================
  Files           520      520              
  Lines         15447    15424      -23     
  Branches       2947     2947              
============================================
- Hits           6406     6405       -1     
+ Misses         8747     8724      -23     
- Partials        294      295       +1     

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