[jdk21u-dev] RFR: 8320331: G1 Full GC Heap verification relies on metadata not reset before verification

[Goetz Lindenmaier]

I backport this as prereq of [JDK-8317809](https://bugs.openjdk.org/browse/JDK-8317809).

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Commit messages:
 - Backport 1629a9059bd2e0f07559a384be4276c7dc13eff2

Changes: https://git.openjdk.org/jdk21u-dev/pull/519/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=519&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320331
  Stats: 33 lines in 5 files changed: 25 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/519.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/519/head:pull/519

PR: https://git.openjdk.org/jdk21u-dev/pull/519