RFR: 8338737: Shenandoah: Reset marking bitmaps after the cycle

[William Kemper]

Clean backport

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Commit messages:
 - 8338737: Shenandoah: Reset marking bitmaps after the cycle

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/173/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=173&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338737
  Stats: 180 lines in 8 files changed: 95 ins; 62 del; 23 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/173.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/173/head:pull/173

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/173