RFR: Merge openjdk/jdk21u-dev:master

[William Kemper]

Merges tag jdk-21.0.6+3

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Commit messages:
 - 8341927: Replace hardcoded security providers with new test.provider.name system property
 - 8335142: compiler/c1/TestTraceLinearScanLevel.java occasionally times out with -Xcomp
 - 8333235: vmTestbase/nsk/jdb/kill/kill001/kill001.java fails with C1
 - 8332112: Update nsk.share.Log to don't print summary during VM shutdown hook
 - 8330278: Have SSLSocketTemplate.doClientSide use loopback address
 - 8240343: JDI stopListening/stoplis001 "FAILED: listening is successfully stopped without starting listening"
 - 8327924: Simplify TrayIconScalingTest.java
 - 8325038: runtime/cds/appcds/ProhibitedPackage.java can fail with UseLargePages
 - 8308429: jvmti/StopThread/stopthrd007 failed with "NoClassDefFoundError: Could not initialize class jdk.internal.misc.VirtualThreads"
 - 8320575: generic type information lost on mandated parameters of record's compact constructors
 - ... and 1 more: https://git.openjdk.org/shenandoah-jdk21u/compare/bb60a427...9bdf2a61

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

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/137/files
  Stats: 1634 lines in 274 files changed: 696 ins; 179 del; 759 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/137.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/137/head:pull/137

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/137