RFR: Merge openjdk/jdk21u:master

[William Kemper]

Merges tag jdk-21.0.8+1

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Commit messages:
 - 8318700: MacOS Zero cannot run gtests due to wrong JVM path
 - 8319690: [AArch64] C2 compilation hits offset_ok_for_immed: assert "c2 compiler bug"
 - 8314236: Overflow in Collections.rotate
 - 8320687: sun.jvmstat.monitor.MonitoredHost.getMonitoredHost() throws unexpected exceptions when invoked concurrently
 - 8353787: Increased number of SHA-384-Digest java.util.jar.Attributes$Name instances leading to higher memory footprint
 - 8352706: httpclient HeadTest does not run on HTTP2
 - 8330598: java/net/httpclient/Http1ChunkedTest.java fails with java.util.MissingFormatArgumentException: Format specifier '%s'
 - 8343891: Test javax/swing/JTabbedPane/TestJTabbedPaneBackgroundColor.java failed
 - 8351086: (fc) Make java/nio/channels/FileChannel/BlockDeviceSize.java test manual
 - 8350224: Test javax/swing/JComboBox/TestComboBoxComponentRendering.java fails in ubuntu 23.x and later
 - ... and 253 more: https://git.openjdk.org/shenandoah-jdk21u/compare/42157792...d5a2f768

The webrev contains the conflicts with master:
 - merge conflicts: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=191&range=00.conflicts

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/191/files
  Stats: 83674 lines in 1494 files changed: 64735 ins; 8729 del; 10210 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/191.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/191/head:pull/191

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/191