RFR: Merge openjdk/jdk21u-dev:master

[William Kemper]

Merges tag jdk-21.0.5-ga

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Commit messages:
 - 8341989: [21u] Back out JDK-8327501 and JDK-8328366
 - 8341674: [21u] Remove designator DEFAULT_PROMOTED_VERSION_PRE=ea for release 21.0.5
 - 8332644: Improve graph optimizations
 - 8331446: Improve deserialization support
 - 8328726: Better Kerberos support
 - 8335713: Enhance vectorization analysis
 - 8328544: Improve handling of vectorization
 - 8328286: Enhance HTTP client
 - 8311208: Improve CDS Support
 - 8307383: Enhance DTLS connections

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

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/130/files
  Stats: 2649 lines in 59 files changed: 2213 ins; 67 del; 369 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/130.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/130/head:pull/130

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/130