RFR: Merge jdk19

[Jesper Wilhelmsson]

Forwardport JDK 19 -> JDK 20

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Commit messages:
 - Merge
 - 8290004: [PPC64] JfrGetCallTrace: assert(_pc != nullptr) failed: must have PC
 - 8289692: JFR: Thread checkpoint no longer enforce mutual exclusion post Loom integration
 - 8289894: A NullPointerException thrown from guard expression
 - 8289729: G1: Incorrect verification logic in G1ConcurrentMark::clear_next_bitmap
 - 8282071: Update java.xml module-info
 - 8290033: ProblemList serviceability/jvmti/GetLocalVariable/GetLocalWithoutSuspendTest.java on windows-x64 in -Xcomp mode
 - 8289697: buffer overflow in MTLVertexCache.m: MTLVertexCache_AddGlyphQuad
 - 8289872: wrong wording in @param doc for HashMap.newHashMap et. al.
 - 8289601: SegmentAllocator::allocateUtf8String(String str) should be clarified for strings containing \0
 - ... and 5 more: https://git.openjdk.org/jdk/compare/46251bc6...0b0d186f

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=jdk&pr=9450&range=00.0
 - jdk19: https://webrevs.openjdk.org/?repo=jdk&pr=9450&range=00.1

Changes: https://git.openjdk.org/jdk/pull/9450/files
  Stats: 411 lines in 43 files changed: 284 ins; 26 del; 101 mod
  Patch: https://git.openjdk.org/jdk/pull/9450.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9450/head:pull/9450

PR: https://git.openjdk.org/jdk/pull/9450