RFR: Merge openjdk/jdk21u:master

[William Kemper]

Merges tag jdk-21.0.10+2

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Commit messages:
 - 8361599: [PPC64] enable missing tests via jtreg requires
 - 8342576: [macos] AppContentTest still fails after JDK-8341443 for same reason on older macOS versions
 - 8341443: [macos] AppContentTest and SigningOptionsTest failed due to "codesign" does not fails with "--app-content" on macOS 15
 - 8311906: Improve robustness of String constructors with mutable array inputs
 - 8315990: Amend problemlisted tests to proper position
 - 8316422: TestIntegerUnsignedDivMod.java triggers "invalid layout" assert in FrameValues::validate
 - 8328299: Convert DnDFileGroupDescriptor.html applet test to main
 - 8352686: Opensource JInternalFrame tests - series3
 - 8352905: Open some JComboBox bugs 1
 - 8352687: Opensource few JInternalFrame and JTextField tests
 - ... and 281 more: https://git.openjdk.org/shenandoah-jdk21u/compare/7f146482...b2eccbc3

The webrev contains the conflicts with master:
 - merge conflicts: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=227&range=00.conflicts

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/227/files
  Stats: 65316 lines in 3049 files changed: 37242 ins; 10619 del; 17455 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/227.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/227/head:pull/227

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/227