[jdk21u-dev] RFR: Merge jdk21u:master

[Goetz Lindenmaier]

Merge build tag 21.0.9-ga from jdk21u to jdk21u-dev

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Commit messages:
 - Merge
 - 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/jdk21u-dev/pull/2372/files
  Stats: 252 lines in 15 files changed: 196 ins; 14 del; 42 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2372.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2372/head:pull/2372

PR: https://git.openjdk.org/jdk21u-dev/pull/2372