RFR: Merge openjdk/jdk21u:master

[William Kemper]

Merges tag jdk-21.0.9-ga

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Commit messages:
 - 8369643: [21u] Remove designator DEFAULT_PROMOTED_VERSION_PRE=ea for release 21.0.9
 - 8360937: Enhance certificate handling
 - 8359454: Enhance String handling
 - 8356294: Enhance Path Factories
 - 8352637: Enhance bytecode verification

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

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/225/files
  Stats: 253 lines in 16 files changed: 196 ins; 14 del; 43 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/225.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/225/head:pull/225

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/225