RFR: 8376195: Convert ThreadLocalAllocBuffer to use Atomic<T> [v3]

[Thomas Schatzl]

> Hi all,
> 
>   please review the change to use `Atomic<T>` in `ThreadLocalAllocBuffer`.
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl 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 seven additional commits since the last revision:

 - Merge branch 'master' into 8376195-convert-threadallocbuffer
 - * revert to original patch sans comment fixes and removal of unused code
 - Revert "* kbarrett review"
   
   This reverts commit cca44442636ff7e0357adf60e402b788070c2a64.
 - Revert "* kbarrett review"
   
   This reverts commit 4fc931e75a7c9911d7a9a4b6f14dc7d91d52d280.
 - * kbarrett review
 - * kbarrett review
 - 8376195
   
   Hi all,
   
     please review the change to use `Atomic<T>` in `ThreadLocalAllocBuffer`.
   
   Testing: gha
   
   Thanks,
     Thomas

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29386/files
  - new: https://git.openjdk.org/jdk/pull/29386/files/4fc931e7..0a299639

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29386&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29386&range=01-02

  Stats: 62687 lines in 1065 files changed: 28164 ins; 19147 del; 15376 mod
  Patch: https://git.openjdk.org/jdk/pull/29386.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29386/head:pull/29386

PR: https://git.openjdk.org/jdk/pull/29386