[master] RFR: Merge jdk

[Roman Kennke]

Merge upstream jdk-20+8

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Commit messages:
 - Merge tag 'jdk-20+8' into merge-jdk-20+8
 - 8290848: LoadLibraryUnload.java still fails with "Too few cleared WeakReferences"
 - Merge
 - 8291006: java/foreign/TestUnsupportedPlatform fails after JDK-8290455
 - 8290455: jck test api/java_lang/foreign/VaList/Empty.html fails on some platforms
 - 8290460: Alpine: disable some panama tests that rely on std::thread
 - 8290074: Remove implicit arguments for RegisterMap constructor
 - 8291289: gc/TestPLABAdaptToMinTLABSize fails after JDK-8289137
 - 8291056: Remove unused Generation::par_promote*()
 - 8285792: Posix signal handler modification checking issues.
 - ... and 1277 more: https://git.openjdk.org/lilliput/compare/9f4a50fe...3d54f6ac

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=lilliput&pr=53&range=00.0
 - jdk: https://webrevs.openjdk.org/?repo=lilliput&pr=53&range=00.1

Changes: https://git.openjdk.org/lilliput/pull/53/files
  Stats: 523876 lines in 7242 files changed: 331933 ins; 136234 del; 55709 mod
  Patch: https://git.openjdk.org/lilliput/pull/53.diff
  Fetch: git fetch https://git.openjdk.org/lilliput pull/53/head:pull/53

PR: https://git.openjdk.org/lilliput/pull/53