RFR: 8323791: Parallel: Using non-atomic for live bytes update during Full GC [v3]

[Albert Mingkun Yang]

> Simple optimization to avoid atomic-operation during Full GC marking.
> 
> Test: Full GC pause length shows ~1% regresion when using single gc-thread and ~20% improvement when using multiple gc-threads using the attached program.

Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  pgc-fullgc-livebyte

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Changes: https://git.openjdk.org/jdk/pull/17442/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17442&range=02
  Stats: 71 lines in 3 files changed: 67 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17442.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17442/head:pull/17442

PR: https://git.openjdk.org/jdk/pull/17442