RFR: Merge jdk19

[Jesper Wilhelmsson]

Forwardport JDK 19 -> JDK 20

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Commit messages:
 - Merge remote-tracking branch 'jdk19/master' into Merge_jdk19
 - 8281969: Bad result for the snippet @link tag if substring/regex consists of whitespace
 - 8290250: Shenandoah: disable Loom for iu mode
 - 8290252: Add TEST.properties to java/nio/channels/FileChannel and move tests out of largeMemory sub-dir

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=jdk&pr=9526&range=00.0
 - jdk19: https://webrevs.openjdk.org/?repo=jdk&pr=9526&range=00.1

Changes: https://git.openjdk.org/jdk/pull/9526/files
  Stats: 68 lines in 7 files changed: 34 ins; 12 del; 22 mod
  Patch: https://git.openjdk.org/jdk/pull/9526.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9526/head:pull/9526

PR: https://git.openjdk.org/jdk/pull/9526