[FLINK-26977] Remove no longer valid tests in JobMasterStopWithSavepointITCase

[dawidwys]

What is the purpose of the change

Tests in JobMasterStopWithSavepointITCase are no longer valid. In
particular the way number of restarts is calculated is wrong. Moreover
cases that were supposed to be tested in the class are already covered
in SavepointITCase.

Verifying this change

This change removes invalid tests.

Tests coverage:

• JobMasterStopWithSavepointITCase#throwingExceptionOnCallbackWithRestartsHelper, JobMasterStopWithSavepointITCase#throwingExceptionOnCallbackWithoutRestartsHelper are covered by SavepointITCase#testStopWithSavepointFailingAfterSnapshotCreation and org.apache.flink.test.checkpointing.SavepointITCase#testStopWithSavepointFailsOverToSavepoint
• JobMasterStopWithSavepointITCase#testRestartCheckpointCoordinatorIfStopWithSavepointFails is covered by SavepointITCase#testStopWithSavepointWithDrainGlobalFailoverIfSavepointAborted

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

CI report:

• 56aa1e0 Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[dawidwys]

@flinkbot run azure

[dmvk]

LGTM 👍

[dmvk]

Maybe the first commit message should be renamed:

Fix SavepointITCase#testStopWithSavepointFailingAfterSnapshotCreation

In my understanding it doesn't really fix anything and just aligns the code path for both schedulers. Is that correct?