Integrated: 8339346: GenShen: Remove even more stale TODOs

[William Kemper]

Clean

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Commit messages:
 - Backport dea5a915a4cb54ba5df59e19a63d3f552d7f69e4

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/100/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=100&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339346
  Stats: 205 lines in 18 files changed: 0 ins; 176 del; 29 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/100.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/100/head:pull/100

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/100