Update BitSwap.java

[MahaleHarsh]

removed the external getBit() method and replaced it with direct bitwise operations to check and swap bits more efficiently.

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized it.
• [x] All filenames are in PascalCase.
• [x] All functions and variable names follow Java naming conventions.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [x] 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 :white_check_mark:

Project coverage is 66.81%. Comparing base (e499d3b) to head (7aeb2df). Report is 129 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5927      +/-   ##
============================================
+ Coverage     66.80%   66.81%   +0.01%     
  Complexity     4501     4501              
============================================
  Files           611      611              
  Lines         16958    16958              
  Branches       3275     3275              
============================================
+ Hits          11328    11330       +2     
+ Misses         5182     5181       -1     
+ Partials        448      447       -1     

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[MahaleHarsh]

I hope my pull request will be accepted

[siriak]

The original version is much more readable in my opinion, so I wouldn't change it. We chose readability over performance here