RFR: 8351091: Shenandoah: global marking context completeness is not accurately maintained

[William Kemper]

Not clean - trivial conflicts with `SIZE_FORMAT/%zu` changes.

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Commit messages:
 - Backport aec1fe0a17fa6801e26a517d4d21656353409f7c

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/190/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=190&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351091
  Stats: 70 lines in 17 files changed: 7 ins; 34 del; 29 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/190.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/190/head:pull/190

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/190