GH-4755: Fix wrong behavior of JobRepository with empty identifying job parameters

[isanghaessi]

Summary

This PR fixes #4755 .
Problem is, job with having zero identifier job parameters are able to restart.
Job what having COMPLETED status should not be able to restart with same Job Parameters.

Changes

• Removed exception condition for job parameters with no identifier job parameters.
• Add test case.
• Edit test cases made assuming empty identifying job parmaeters can be restarted.

[isanghaessi]

Hi, @fmbenhassine.
Can you please review this PR when has chance?
I am very interesting spring batch project and using it.
I hope this ambigious behavior will be fixed.
Thanks.

[fmbenhassine]

Hi @isanghaessi ,

Thank you for the PR. #4755 is planned for v6, so I will check your PR soon. I will keep you posted.

[fmbenhassine]

I am looking into including this PR in v6.0.0-RC2 if possible. Can you please rebase it on the latest main? Thank you upfront.

[isanghaessi]

Hi @fmbenhassine,
Since there were too many changes in the middle, I force pushced changes.

I moved my changes from SimpleJobRepository from TaskExecutorJobLauncher.
I saw restartability logic moved from JobRepository to JobOperator - 90d8959.

					if (!identifyingJobParameters.isEmpty()
							&& (status == BatchStatus.COMPLETED || status == BatchStatus.ABANDONED)) {
						throw new JobInstanceAlreadyCompleteException(
								"A job instance already exists and is complete for identifying parameters="
										+ identifyingJobParameters + ".  If you want to run this job again, "
										+ "change the parameters.");
					}

It is hard to change test cases in core package because they are almost broken and disabled.
And so it is hard to add test case.
At least, I checked that test cases in other packages are not broken.

Please let me know if there is anything I am missing.