[code-reflection] Integrated: Refactored Blockgroup also renamed some helper functs

[Gary Frost]

HATified the transformer and op filters from original code. 

Also renamed some of the core OpHelper function names to be consistent

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Commit messages:
 - Refactored Blockgroup also renamed some helper functs

Changes: https://git.openjdk.org/babylon/pull/827/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=827&range=00
  Stats: 90 lines in 8 files changed: 10 ins; 14 del; 66 mod
  Patch: https://git.openjdk.org/babylon/pull/827.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/827/head:pull/827

PR: https://git.openjdk.org/babylon/pull/827