[code-reflection] RFR: Unreflect tests [v5]

[Adam Sotona]

> This PR implement `Unreflect` test tool and re-runs tests in the unreflected form.
> 
> `TestSwitchExpressionOp` and `TestSwitchStatementOp` yet to be temporary excluded as failing  (see [JDK-8373573](https://bugs.openjdk.org/browse/JDK-8373573)).

Adam Sotona has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:

 - unreflecting nest members
   
 - Merge branch 'code-reflection' into unreflect-tests
 - unreflect lambdas
   
 - test tags cleanup
   
 - nit fixes
   
 - obsolete debug print
   
 - new line
   
 - simplification
   
 - fixed long lines
   
 - unreflect tests

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

Changes:
  - all: https://git.openjdk.org/babylon/pull/762/files
  - new: https://git.openjdk.org/babylon/pull/762/files/0ed2a375..bcf00fd9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=762&range=04
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=762&range=03-04

  Stats: 21481 lines in 314 files changed: 9971 ins; 10394 del; 1116 mod
  Patch: https://git.openjdk.org/babylon/pull/762.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/762/head:pull/762

PR: https://git.openjdk.org/babylon/pull/762