RFR: Merge openjdk/jdk21u-dev:master

[William Kemper]

Merges tag jdk-21.0.3+2

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

Commit messages:
 - 8325096: Test java/security/cert/CertPathBuilder/akiExt/AKISerialNumber.java is failing
 - 8321410: Shenandoah: Remove ShenandoahSuspendibleWorkers flag
 - 8322957: Generational ZGC: Relocation selection must join the STS
 - 8313670: Simplify shared lib name handling code in some tests
 - 8309697: [TESTBUG] Remove "@requires vm.flagless" from jtreg vectorization tests
 - 8323637: Capture hotspot replay files in GHA
 - 8324937: GHA: Avoid multiple test suites per job
 - 8320052: Zero: Use __atomic built-ins for atomic RMW operations
 - 8319382: com/sun/jdi/JdwpAllowTest.java shows failures on AIX if prefixLen of mask is larger than 32 in IPv6 case
 - 8323101: C2: assert(n->in(0) == nullptr) failed: divisions with zero check should already have bailed out earlier in split-if
 - ... and 201 more: https://git.openjdk.org/shenandoah-jdk21u/compare/375769c6...57956950

The webrev contains the conflicts with master:
 - merge conflicts: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=20&range=00.conflicts

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/20/files
  Stats: 31479 lines in 1396 files changed: 16522 ins; 6158 del; 8799 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/20.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/20/head:pull/20

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/20