[code-reflection] Integrated: More refactoring of HAT transformers and phases to use new helpers

[Gary Frost]

Slowing aligning the phase transformers to use new tools/helpers/apis

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Commit messages:
 - More refactoring of HAT transformers and phases to use new helpers

Changes: https://git.openjdk.org/babylon/pull/841/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=841&range=00
  Stats: 129 lines in 5 files changed: 16 ins; 54 del; 59 mod
  Patch: https://git.openjdk.org/babylon/pull/841.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/841/head:pull/841

PR: https://git.openjdk.org/babylon/pull/841