[code-reflection] RFR: Code reflection synthetic class generation moved to JavaCompiler::genCode [v3]

[Adam Sotona]

> Prototype of code reflection synthetic class generation move to `JavaCompiler::genCode`.
> 
> - collected ops are attached to the `ReflectMethods.JCReflectMethodsClassDecl`, an internal extension of `JCTree.JCClassDecl`
> - new `genCode` method is added to `CodeReflectionTransformer` interface
> - `JavaCompiler` calls `CodeReflectionTransformer::genCode` inside its `genCode` method 
> - implementation in `ReflectMethods.Provider` calls `OpBuilder` and `BytecodeGenerator` and generates the synthetic inner class

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  removed obsolete method

-------------

Changes:
  - all: https://git.openjdk.org/babylon/pull/689/files
  - new: https://git.openjdk.org/babylon/pull/689/files/7ece448f..47dd7ee7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=689&range=02
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=689&range=01-02

  Stats: 6 lines in 1 file changed: 0 ins; 6 del; 0 mod
  Patch: https://git.openjdk.org/babylon/pull/689.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/689/head:pull/689

PR: https://git.openjdk.org/babylon/pull/689