RFR: 8322732: ForkJoinPool may underutilize cores in async mode [v7]

[Doug Lea]

> This set of changes address causes of poor utilization with small numbers of cores due to overly aggressive contention avoidance. A number of further adjustments were needed to still avoid most contention effects in deployments with large numbers of cores

Doug Lea has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 41 additional commits since the last revision:

 - Merge branch 'openjdk:master' into JDK-8322732
 - Add test for utilization with interdependent tasks
 - Un-misplace onSpinWait call
 - Adjust control flow
 - Reduce memory stalls
 - Merge branch 'openjdk:master' into JDK-8322732
 - More performance tradoffs
 - Address review comments
 - Merge branch 'openjdk:master' into JDK-8322732
 - Repack some fields; adjust control flow
 - ... and 31 more: https://git.openjdk.org/jdk/compare/cc3280e5...cf5fe55c

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19131/files
  - new: https://git.openjdk.org/jdk/pull/19131/files/a262f6c6..cf5fe55c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19131&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19131&range=05-06

  Stats: 23145 lines in 634 files changed: 14865 ins; 4679 del; 3601 mod
  Patch: https://git.openjdk.org/jdk/pull/19131.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19131/head:pull/19131

PR: https://git.openjdk.org/jdk/pull/19131