RFR: 8332254: GenShen: Remove obsolete comments and revert unnecessary formatting changes

[William Kemper]

Clean backport

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Commit messages:
 - Backport dfa788667714b4ec7e0e235e9c0c58cc5e3ceab4

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/48/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=48&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332254
  Stats: 11 lines in 1 file changed: 1 ins; 5 del; 5 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/48.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/48/head:pull/48

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/48