[jdk21u-dev] RFR: 8327501: Common ForkJoinPool prevents class unloading in some cases [v2]

[Aleksey Shipilev]

> The change is stabilizing in mainline, but it looks simple, so we start testing it for JDK 21 pickup here.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `all`

Aleksey Shipilev 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 two additional commits since the last revision:

 - Merge branch 'master' into JDK-8327501-fjp-classloader-leak
 - Backport 53c4714aab2e072ba18631875dcaa3b2d5d22243

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

Changes:
  - all: https://git.openjdk.org/jdk21u-dev/pull/338/files
  - new: https://git.openjdk.org/jdk21u-dev/pull/338/files/bce8bcfc..f17aeca1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=338&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=338&range=00-01

  Stats: 3079 lines in 78 files changed: 2430 ins; 370 del; 279 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/338.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/338/head:pull/338

PR: https://git.openjdk.org/jdk21u-dev/pull/338