[code-reflection] RFR: Cleanups

[Paul Sandoz]

Clean up vestiges of code required prior to being in the `jdk.incubator.code` module

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Commit messages:
 - Cleanups.

Changes: https://git.openjdk.org/babylon/pull/463/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=463&range=00
  Stats: 16 lines in 4 files changed: 1 ins; 9 del; 6 mod
  Patch: https://git.openjdk.org/babylon/pull/463.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/463/head:pull/463

PR: https://git.openjdk.org/babylon/pull/463