Improving a unit test in GitSCMTest

[raghavgarg098]

Improving unit test testCommitMessageIsPrintedToLogs

The test case implemented intially was inefficient. It was running the freestyle project and then calling the checkout API again to check for the logged value. Since, running the pipeline job executes the chekout step as well there is no need to invoke checkout step again.Also instead of using mocks we can use waitForMessage API which checks for logged values.

Checklist

• I have read the CONTRIBUTING doc
• I have added tests that verify my changes
• Unit tests pass locally with my changes
• No Javadoc warnings were introduced with my changes
• No spotbugs warnings were introduced with my changes
• Online help has been added and reviewed for any new or modified fields
• Any dependent changes have been merged and published in upstream modules (like git-client-plugin)

Types of changes

• Dependency or infrastructure update
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)