[FLINK-38272][runtime] Fix unstable BatchJobRecoveryTest

[noorall]

What is the purpose of the change

Fix unstable BatchJobRecoveryTest

Brief change log

Avoid test failures due to task restarts after failover.

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:

• b943355 Azure: SUCCESS

Bot commands

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

[noorall]

@zhuzhurk Thanks for your review. I've pushed a fixup commit to address your comments.

[zhuzhurk]

LGTM.

[noorall]

@flinkbot run azure