HDDS-8005. Fixed intermittent failure in TestOmSnapshot.testSnapDiffWithMultipleSSTs

[hemantk-12]

What changes were proposed in this pull request?

TestOmSnapshot.testSnapDiffWithMultipleSSTs was failing all the time because snapshot diff is an async API and when a job is submitted for the first time, it always returns empty diff list with IN_PROGRESS status. User is supposed to make second call to fetch the results, once job is DONE. TestOmSnapshot.testSnapDiffWithMultipleSSTs was only making one call which only submits the request and returned empty diff response as mentioned above.
This change is to call snap diff after job to DONE to fetch complete diff report.

What is the link to the Apache JIRA

HDDS-8005

How was this patch tested?

• Ran the test locally and on fork: https://github.com/hemantk-12/ozone/actions/runs/7620429542
• Flaky-test-check workflow run: https://github.com/hemantk-12/ozone/actions/runs/7630045775

[sadanand48]

Thanks @hemantk-12 , overall change looks good . Could you also please run the flaky test workflow for this test a few times.

[aswinshakil]

Thanks for the patch. We can just run thefalky-test-check just to be sure. Otherwise I'm good with the changes.

[hemantk-12]

Initially, I didn't run the flaky-test-check because this test was marked Unhealthy not Flaky which means it failed all the times.

Just to be sure as suggested above, I ran it for 5x10 for TestOmSnapshotObjectStore: https://github.com/hemantk-12/ozone/actions/runs/7630045775 and it passed all the times.

[hemantk-12]

Thanks @sadanand48 and @aswinshakil for the review.