RFR: 8319376: ParallelGC: Forwarded objects found during heap inspection [v6]

[Roman Kennke]

> See JBS issue for details.
> 
> Testing:
>  - [x] gc/logging/TestUnifiedLoggingSwitchStress.java -XX:+UseParallelGC
>  - [x] tier1 -XX:+UseParallelGC
>  - [ ] tier2 -XX:+UseParallelGC
>  - [ ] hotspot_gc

Roman Kennke has updated the pull request incrementally with one additional commit since the last revision:

  Do *not* handle self-forwarded objects

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16494/files
  - new: https://git.openjdk.org/jdk/pull/16494/files/988b96e6..6ba7c713

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16494&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16494&range=04-05

  Stats: 6 lines in 1 file changed: 5 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16494.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16494/head:pull/16494

PR: https://git.openjdk.org/jdk/pull/16494