[FLINK-30852][runtime] Checking task cancelation explicitly rather than failing the cancel method

[akalash]

What is the purpose of the change

These changes fix the exception from TestInvokableCorrect#cancel which is 1) incorrect 2) doesn't really fail test

Brief change log

• Explicit assert for the task cancelation in tests
• Removed the exception from TestInvokableCorrect#cancel since in some test it isn't correct

Verifying this change

It is test itself

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:

• 1886747 Azure: SUCCESS

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[akalash]

@rkhachatryan Are you familiar with these tests? May I ask you to take a look at this PR?

[rkhachatryan]

Thanks for the PR @akalash LGTM