RFR: Merge jfx20 [v2]

[Kevin Rushforth]

> Final merge of `jfx20` into `master`.

Kevin Rushforth has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 44 commits:

 - Merge jfx20
 - 8303680: Virtual Flow freezes after calling scrollTo and scrollPixels in succession
   
   Reviewed-by: angorya, jvos
 - 8301009: Update libxml2 to 2.10.3
   
   Reviewed-by: kcr, sykora
 - 8178368: Right alignment of text fields and alignment of prompt text works incorrectly
   
   Reviewed-by: angorya, kcr
 - 8299968: Second call to Stage.setScene() create sizing issue with uiScale > 1.0
   
   Reviewed-by: kcr, arapte
 - 8302355: Public API for Toolkit.canStartNestedEventLoop()
   
   Reviewed-by: kcr, arapte
 - 8302797: ArrayIndexOutOfBoundsException in TextRun.getWrapIndex()
   
   Reviewed-by: angorya, kcr
 - 8090123: Items are no longer visible when collection is changed
   
   Reviewed-by: angorya, kcr
 - 8303217: Webview loaded webpage is not showing play, volume related buttons for embeded Audio/Video elements
   8300954: HTML default Range input control not rendered
   
   Co-authored-by: Hima Bindu Meda <hmeda at openjdk.org>
   Reviewed-by: kcr, hmeda
 - 8300872: WebView's ColorChooser fails to initialize when running in security context
   
   Reviewed-by: kcr, mstrauss
 - ... and 34 more: https://git.openjdk.org/jfx/compare/f2118a13...a98714a2

-------------

Changes: https://git.openjdk.org/jfx/pull/1062/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1062&range=01
  Stats: 207648 lines in 5810 files changed: 121713 ins; 46442 del; 39493 mod
  Patch: https://git.openjdk.org/jfx/pull/1062.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1062/head:pull/1062

PR: https://git.openjdk.org/jfx/pull/1062