[jdk21u-dev] RFR: Merge jdk21u:master

[Goetz Lindenmaier]

Merge build tag 21.0.3+7 from jdk21u to jdk21u-dev

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Commit messages:
 - Merge
 - 8327391: Add SipHash attribution file

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

Changes: https://git.openjdk.org/jdk21u-dev/pull/386/files
  Stats: 150 lines in 1 file changed: 150 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/386.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/386/head:pull/386

PR: https://git.openjdk.org/jdk21u-dev/pull/386