Added more test cases as per the issue #6282

[audhee]

• 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

Added 20+ test cases for "Binary_Pow":

• Base & exponent variations :
• 0^0 handling :
• Negative base behavior :
• Overflow/large number checks :
• Negative exponent exception testing :

Follows repo structure & uses JUnit 5
Resolves issue #6282