[FLINK-34518][runtime] Fixes AdaptiveScheduler#suspend bug when the job is suspended during Restarting phase

[XComp]

What is the purpose of the change

See comment in FLINK-34518 for more details.

Brief change log

• Overwrites the ExecutionGraph's state when suspending the job in the Restarting phase: The actually state might be CANCELLED which can result in a HA data cleanup because it's a globally-terminal state which we don't want when restarting the job. The cancellation of the ExecutionGraph is more like an implementation detail of the Restarting state and shouldn't be exposed.

Verifying this change

• Added unit test to cover this scenario

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, Kubernetes/Yarn, ZooKeeper: yes
• The S3 file system connector: no

Documentation

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

[flinkbot]

CI report:

• 3176a98 Azure: SUCCESS

Bot commands

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

[gyfora]

Tested this with the k8s operator on 1.18, could not reproduce the issues we have seen before