RFR: 8373403: [TESTBUG] TestG1ClassUnloadingHWM.java could fail with large G1HeapRegionSize and small InitialHeapSize [v3]

[Man Cao]

> Hi all,
> 
> Could anyone review this test-only improvement to make TestG1ClassUnloadingHWM.java more robust in various configurations?
> See https://bugs.openjdk.org/browse/JDK-8373403 for more details.
> 
> -Man

Man Cao has updated the pull request incrementally with one additional commit since the last revision:

  Also check for 'Metadata GC Threshold' for young GC

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/28738/files
  - new: https://git.openjdk.org/jdk/pull/28738/files/6c6fbfe9..70e88efa

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28738&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28738&range=01-02

  Stats: 7 lines in 1 file changed: 2 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/28738.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28738/head:pull/28738

PR: https://git.openjdk.org/jdk/pull/28738