RFR: Merge openjdk/jdk21u-dev:master

[William Kemper]

Merges tag jdk-21.0.4+4

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Commit messages:
 - 8321107: Add more test cases for JDK-8319372
 - 8316138: Add GlobalSign 2 TLS root certificates
 - 8320715: Improve the tests of test/hotspot/jtreg/compiler/intrinsics/float16
 - 8331298: avoid alignment checks in UBSAN enabled build
 - 8312218: Print additional debug information when hitting assert(in_hash)
 - 8308144: Uncontrolled memory consumption in SSLFlowDelegate.Reader
 - 8299023: TestPLABResize.java and TestPLABPromotion.java are failing intermittently
 - 8329663: hs_err file event log entry for thread adding/removing should print current thread
 - 8330615: avoid signed integer overflows in zip_util.c readCen / hashN
 - 8331167: UBSan enabled build fails in adlc on macOS
 - ... and 5 more: https://git.openjdk.org/shenandoah-jdk21u/compare/035e3144...c44d4e93

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/51/files
  Stats: 1020 lines in 27 files changed: 947 ins; 0 del; 73 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/51.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/51/head:pull/51

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/51