[FLINK-32064][table-planner] Add subdirectory of test output file for JsonPlanTest to indicate the plan's version

[LadyForest]

What is the purpose of the change

This PR is a refactor for all JsonPlanTest, as preparation for upgrading some ExecNodes to version 2.

Brief change log

• Add a subdirectory execNodeVersion=1 under each JsonPlanTest's output file.
• Refactor the verifyJsonPlan method, to walk through all subdirectories under each PlanTest, check JsonSerDe for each version, and use the highest version to check object <--> JSON works as expected.

Verifying this change

This change is already covered by existing tests.

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: no
• The S3 file system connector: no

Documentation

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

[flinkbot]

CI report:

• c838025 Azure: SUCCESS

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[LadyForest]

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[LadyForest]

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[LadyForest]

After an offline discussion with @godfreyhe, we have decided to select some of the existing JSON files as test specs for the upgrade tests. We will directly adapt the remaining tests to the new exec version to avoid excessive redundancy in the test files.