Integrated: 8338780: GenShen: Fix up some comments

[William Kemper]

Clean.

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Commit messages:
 - Backport 977200a0c073e90754f56730477d0fa32fd7ec9a

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/95/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=95&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338780
  Stats: 114 lines in 4 files changed: 34 ins; 72 del; 8 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/95.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/95/head:pull/95

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/95