RFR: Merge jfx20 [v2]

[Kevin Rushforth]

> Merge `jfx20` branch into `master`.

Kevin Rushforth has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge jfx20
 - 8299681: Change JavaFX release version to 21
   
   Reviewed-by: arapte, angorya

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Changes:
  - all: https://git.openjdk.org/jfx/pull/998/files
  - new: https://git.openjdk.org/jfx/pull/998/files/d64b546a..d64b546a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=998&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=998&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/998.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/998/head:pull/998

PR: https://git.openjdk.org/jfx/pull/998