[FLINK-35403] Allow Skipping Invocation of Function Calls While Constant-folding

[AlanConfluent]

What is the purpose of the change

This PR adds a new method to FunctionDefinition, supportsConstantFolding which indicates of a function call should have constant expression reduction done during planning time. For example, AddOne(10) could be reduced to 11 by invoking AddOne during planning time. This is the default and current Flink functionality.

This addition allows overriding the default behavior and returning false, which would keep the expression intact, to be invoked at runtime instead.

This functionality and motivation is covered in more detail in FLIP 452.

Verifying this change

• Added new test cases to ExpressionReductionRulesTest.
  • These test that existing plans are unchanged
  • New tests show that disabling constant folding also keeps plans without reducing away the invocation

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): (yes)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
  • It shouldn't affect default behavior, which is to constant fold
• 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 introduce a new feature? (yes)
• If yes, how is the feature documented? (docs)

[flinkbot]

CI report:

• 78c4501 Azure: SUCCESS

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[twalthr]

Nice and clean PR with good documentation. Nothing to add here.