[jdk21u-dev] RFR: Merge jdk21u:master

[Goetz Lindenmaier]

Merge build tag 21.0.10+6 from jdk21u to jdk21u-dev

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Commit messages:
 - Merge
 - 8317970: Bump target macosx-x64 version to 11.00.00
 - 8372534: Update Libpng to 1.6.51

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2538&range=00.0
 - jdk21u:master: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2538&range=00.1

Changes: https://git.openjdk.org/jdk21u-dev/pull/2538/files
  Stats: 660 lines in 23 files changed: 297 ins; 224 del; 139 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2538.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2538/head:pull/2538

PR: https://git.openjdk.org/jdk21u-dev/pull/2538