RFR: Merge openjdk/jdk:master

[William Kemper]

Merges tag jdk-21+4

-------------

Commit messages:
 - Merge tag 'jdk-21+4' into merge-jdk-21-4
 - 8299439: java/text/Format/NumberFormat/CurrencyFormat.java fails for hr_HR
 - 8299563: Fix typos
 - 8219810: javac throws NullPointerException
 - 8200610: Compiling fails with java.nio.file.ReadOnlyFileSystemException
 - Merge
 - 8299476: PPC64 Zero build fails after JDK-8286302
 - 8293824: gc/whitebox/TestConcMarkCycleWB.java failed "RuntimeException: assertTrue: expected true, was false"
 - 8299483: ProblemList java/text/Format/NumberFormat/CurrencyFormat.java
 - 8298324: Unable to run shell test with make
 - ... and 72 more: https://git.openjdk.org/shenandoah/compare/c5774a09...55fe3430

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=shenandoah&pr=196&range=00.0
 - openjdk/jdk:master: https://webrevs.openjdk.org/?repo=shenandoah&pr=196&range=00.1

Changes: https://git.openjdk.org/shenandoah/pull/196/files
  Stats: 5313 lines in 488 files changed: 2252 ins; 1955 del; 1106 mod
  Patch: https://git.openjdk.org/shenandoah/pull/196.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah pull/196/head:pull/196

PR: https://git.openjdk.org/shenandoah/pull/196