fix(java): Fix EnumSetSerializer for enums with overriding methods

[NotLebedev]

Why?

Fix EnumSetSerializers for enums that have overriding methods in vairants:

  enum TestEnumWithMethods {
    A {
      @Override
      public void foo() {
          System.out.println("A");
      }
    },
    B,
    C {
      @Override
      public void foo() {
      }
    },
    D;

    public void foo() {
        System.out.println("default");
    }
  }

What does this PR do?

EnumSetSerializer now correctly unwraps types of variants that extend base enum type. Doing it this way instead of writing class of variant and unwrapping it in read prevents writing additional classes for enum variants.

Related issues

• Fixes [Java] Incorrect serialization of EnumSet if enum has variants with overriding methods #3306

Does this PR introduce any user-facing change?

• Does this PR introduce any public API change?
• Does this PR introduce any binary protocol compatibility change?

This PR changes class of contained enum that EnumSetSerializer writes. Instead of writing class of enum variant if this variant extends base enum class it always writes class of base enum. This however does not break any existing code since previously EnumSets of classes with overriding methods could not be deserialized at all

Benchmark

[chaokunyang]

LGTM