RFR: Merge openjdk/jdk21u-dev:master

[William Kemper]

Merges tag jdk-21.0.3+6

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Commit messages:
 - 8322750: Test "api/java_awt/interactive/SystemTrayTests.html" failed because A blue ball icon is added outside of the system tray
 - 8323664: java/awt/font/JNICheck/FreeTypeScalerJNICheck.java still fails with JNI warning on some Windows configurations
 - 8325496: Make TrimNativeHeapInterval a product switch
 - 8321151: JDK-8294427 breaks Windows L&F on all older Windows versions
 - 8325876: crashes in docker container tests on Linuxppc64le Power8 machines
 - 8325470: [AIX] use fclose after fopen in read_psinfo
 - 8320303: Allow PassFailJFrame to accept single window creator
 - 8326000: Remove obsolete comments for class sun.security.ssl.SunJSSE
 - 8314835: gtest wrappers should be marked as flagless
 - 8325254: CKA_TOKEN private and secret keys are not necessarily sensitive
 - ... and 35 more: https://git.openjdk.org/shenandoah-jdk21u/compare/57956950...29bf21fd

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

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/26/files
  Stats: 3260 lines in 177 files changed: 2507 ins; 194 del; 559 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/26.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/26/head:pull/26

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/26