RFR: 8336707: Contention of ForkJoinPool grows when stealing works [v18]

[Doug Lea]

> This addresses tendencies in previous update to increase fencing, scanning, and signalling that can increase contention, and slow down performance especially on ARM platforms. It also uses more ARM-friendly constructions to reduce overhead (leading to several changes that all of the same form),

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 36 additional commits since the last revision:

 - Merge branch 'openjdk:master' into JDK-8336707
 - More shutdown streamlining
 - Don't report termination while cancellations in progress
 - Reduce read contention
 - Merge branch 'openjdk:master' into JDK-8336707
 - Reduce shutdown overhead and contention
 - dropWaiters now back to releaseAll
 - Merge branch 'openjdk:master' into JDK-8336707
 - reduce shutdown overhead
 - For starvation check #7
 - ... and 26 more: https://git.openjdk.org/jdk/compare/340f0ba8...f657543b

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21507/files
  - new: https://git.openjdk.org/jdk/pull/21507/files/7b86aac4..f657543b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21507&range=17
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21507&range=16-17

  Stats: 128924 lines in 665 files changed: 102232 ins; 9181 del; 17511 mod
  Patch: https://git.openjdk.org/jdk/pull/21507.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21507/head:pull/21507

PR: https://git.openjdk.org/jdk/pull/21507