RFR: 8337242: GenShen: Remove unnecessary copyright changes

[William Kemper]

The Amazon copyright has been added to some files that we've hardly changed. Removing the copyright reduces the total number of files changed in the forthcoming generational mode pull request.

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Commit messages:
 - Remove unnecessary Amazon copyright from little changed files

Changes: https://git.openjdk.org/shenandoah/pull/462/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=462&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/pull/462.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/462/head:pull/462

PR: https://git.openjdk.org/shenandoah/pull/462