RFR: Merge jfx20

[Kevin Rushforth]

Merge `jfx20` into `master`.

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Commit messages:
 - Merge jfx20
 - 8300705: Update boot JDK to 19.0.2
 - 8290863: Update the documentation of Virtualized controls to include the best practice of not using Nodes directly in the item list
 - 8300013: Node.focusWithin doesn't account for nested focused nodes

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=jfx&pr=1020&range=00.0
 - jfx20: https://webrevs.openjdk.org/?repo=jfx&pr=1020&range=00.1

Changes: https://git.openjdk.org/jfx/pull/1020/files
  Stats: 360 lines in 9 files changed: 314 ins; 2 del; 44 mod
  Patch: https://git.openjdk.org/jfx/pull/1020.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1020/head:pull/1020

PR: https://git.openjdk.org/jfx/pull/1020