[jdk25u-dev] RFR: 8307495: Specialize atomic bitset functions for aix-ppc [v2]

[David Briemann]

> This pull request contains a backport of commit [c9cbd31f](https://github.com/openjdk/jdk/commit/c9cbd31f8575a25c4decd68dc645378c5ba2bad0) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.
> 
> The commit being backported was authored by David Briemann on 15 Oct 2025 and was reviewed by Martin Doerr and Richard Reingruber.
> 
> A merge conflict was resolved, that was created by renaming files: https://github.com/openjdk/jdk/pull/27245
> Otherwise the backport is clean.

David Briemann has updated the pull request incrementally with one additional commit since the last revision:

  revert class name because of 8367014

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

Changes:
  - all: https://git.openjdk.org/jdk25u-dev/pull/24/files
  - new: https://git.openjdk.org/jdk25u-dev/pull/24/files/d34d45ce..78d202eb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=24&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=24&range=00-01

  Stats: 12 lines in 1 file changed: 0 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/jdk25u-dev/pull/24.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u-dev.git pull/24/head:pull/24

PR: https://git.openjdk.org/jdk25u-dev/pull/24