[FLINK-9293] [runtime] SlotPool should check slot id when accepting a slot offer with existing allocation id

[shuai-xu]

What is the purpose of the change

This pull request fix that job master will accept multi slot offers with same allocation id and make the later slots leak.

Verifying this change

This change added tests and can be verified as follows:

(example:)

• Run the SlotPoolTest

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

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

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

[StephanEwen]

Good catch! Thank you for the PR.

Will try to review this asap...