Integrated: 8337242: GenShen: Remove unnecessary copyright changes

[William Kemper]

Clean backport.

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Commit messages:
 - Backport 4f96b5d29652c7d24adca6d77804926f2bb5ef55

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/78/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=78&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337242
  Stats: 6 lines in 6 files changed: 1 ins; 5 del; 0 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/78.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/78/head:pull/78

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/78