RFR: Merge jdk20

[Jesper Wilhelmsson]

Forwardport JDK 20 -> JDK 21

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Commit messages:
 - Merge
 - 8298225: [AIX] Disable PPC64LE continuations on AIX
 - 8298463: tools/javac/modules/EdgeCases.java fails on Windows after JDK-8297988
 - 8298353: C2 fails with assert(opaq->outcnt() == 1 && opaq->in(1) == limit) failed
 - 8298340: java/net/httpclient/CancelRequestTest.java fails with AssertionError: Found some subscribers for testPostInterrupt
 - 8298455: JFR: Add logging to TestClose.java
 - 8297988: NPE in JavacTypes.getOverriddenMethods from doclint
 - 8298402: ProblemList javax/swing/JFileChooser/4847375/bug4847375.java on windows-x64

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=jdk&pr=11614&range=00.0
 - jdk20: https://webrevs.openjdk.org/?repo=jdk&pr=11614&range=00.1

Changes: https://git.openjdk.org/jdk/pull/11614/files
  Stats: 262 lines in 13 files changed: 250 ins; 1 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/11614.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11614/head:pull/11614

PR: https://git.openjdk.org/jdk/pull/11614