[FLINK-39273][table-common] Fix argument name conflict when UDF method contains lambda expression

[dylanhz]

What is the purpose of the change

Fix a bug where UDF type inference throws "Argument name conflict" when a method (e.g. eval, accumulate) contains a lambda expression that captures its own parameters.

The ASM-based ParameterExtractor in ExtractionUtils matched target methods only by bytecode descriptor, ignoring the method name. When a lambda captures parameters of the enclosing eval method, the Java compiler generates a lambda$eval$N synthetic static method with the same descriptor. The ParameterExtractor visits both the real eval and the synthetic method, causing the lambda's local variable names (starting at slot 0) to overwrite the instance method's parameter entries (where slot 0 is this) in the shared TreeMap, producing duplicate names and triggering the validation error.

Brief change log

• Store methodName in ParameterExtractor (method.getName() for methods, "<init>" for constructors)
• Match on both name.equals(methodName) && descriptor.equals(methodDescriptor) in visitMethod to avoid visiting lambda synthetic methods

Verifying this change

This change added tests and can be verified as follows:

• Added a unit test in ExtractionUtilsTest that directly verifies extractExecutableNames returns correct parameter names for a method containing a lambda that captures its own parameters
• Added an integration test in TypeInferenceExtractorTest that verifies end-to-end type inference succeeds for a ScalarFunction with lambda capture

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

[flinkbot]

CI report:

• 66a45f0 Azure: SUCCESS

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