RFR: 8343704: Bad GC parallelism with processing Cleaner queues [v2]

[Aleksey Shipilev]

> See the bug for more discussion and reproducer. This PR replaces the ad-hoc linked list with the `ArrayList` wrapper that manages synchronization, search and replacements efficiently. Arrays are easy targets for GC. There are possible improvements here, most glaring is parallelism that is currently knee-capped by global synchronization. The synchronization scheme follows what we have in original code, and I think it is safer to continue with it right now.
> 
> I'll put performance data in a separate comment.
> 
> Additional testing:
>  - [x] Original reproducer improves drastically
>  - [x] New microbenchmark shows no regression on "churning" tests, which covers insertion/removal perf
>  - [x] New microbenchmark shows improvement on Full GC times (crude, but repeatable), serves as a proxy for reproducer
>  - [x] `java/lang/ref` tests in release 
>  - [ ] `all` tests in fastdebug

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Touchups: assert index, polish commits

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22043/files
  - new: https://git.openjdk.org/jdk/pull/22043/files/69d2d189..f791d3ce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22043&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22043&range=00-01

  Stats: 13 lines in 2 files changed: 6 ins; 3 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/22043.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22043/head:pull/22043

PR: https://git.openjdk.org/jdk/pull/22043