RFR: Merge openjdk/jdk21u:master

[William Kemper]

Merges tag jdk-21.0.7+4

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Commit messages:
 - 8317808: HTTP/2 stream cancelImpl may leave subscriber registered
 - 8344581: [TESTBUG] java/awt/Robot/ScreenCaptureRobotTest.java failing on macOS
 - 8339356: Test javax/net/ssl/SSLSocket/Tls13PacketSize.java failed with java.net.SocketException: An established connection was aborted by the software in your host machine
 - 8342635: javax/swing/JFileChooser/FileSystemView/WindowsDefaultIconSizeTest.java creates tmp file in src dir
 - 8349039: Adjust exception No type named <ThreadType> in database
 - 8327476: Upgrade JLine to 3.26.1
 - 8349729: [21u] AIX jtreg tests fail to compile with qvisibility=hidden
 - 8348675: TrayIcon tests fail in Ubuntu 24.10 Wayland
 - 8346828: javax/swing/JScrollBar/4865918/bug4865918.java still fails in CI
 - 8346324: javax/swing/JScrollBar/4865918/bug4865918.java fails in CI
 - ... and 10 more: https://git.openjdk.org/shenandoah-jdk21u/compare/b7d92cd0...58069061

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

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/157/files
  Stats: 8524 lines in 155 files changed: 3751 ins; 1651 del; 3122 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/157.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/157/head:pull/157

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/157