refactor: ArrayLeftRotationTest

[alxkm]

Class cleanup.
Readability improvements.
Added test.

• 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 47.50%. Comparing base (3187b1f) to head (c163d8c).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5389      +/-   ##
============================================
+ Coverage     47.49%   47.50%   +0.01%     
- Complexity     2930     2932       +2     
============================================
  Files           524      524              
  Lines         15314    15317       +3     
  Branches       2905     2907       +2     
============================================
+ Hits           7273     7277       +4     
+ Misses         7740     7739       -1     
  Partials        301      301              

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