Remove test conditionals for unsupported git versions

[MarkEWaite]

Remove test conditionals for unsupported git versions

Operating systems that provided versions of command line git older than 2.30 are no longer supported by their upstream providers and are thus no longer supported by the Jenkins project. Remove the special cases in the tests for those unsupported operating systems.

Testing done

Confirmed that automated tests pass with Java 21 on Linux. Rely on ci.jenkins.io to test Windows and Java 17.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue