RFR: 8290866: Apple Color Emoji turns gray after JavaFX version 18 [v3]

[Phil Race]

> This fix properly supports colour rendering of Emoji on macOS
> 
> 
> On other platforms the Emoji will be rendered as ordinary greyscale glyphs - if there is font
> support for the requested code point.
> 
> A simple manual test is provided which uses a Text node, Label control
> and editable TextField control.
> 
> Some highlights of the code
> - To determine if it is a color emoji glyph probe the 'sbix' font table which is what is used by Apple
> - Text runs now break at an Emoji glyph
> - The Emoji is retrieved as an BGRA image - ie 4 channel including alpha
> - It was necessary to retrieve the Emoji glyph bounds via a different CoreText API since
>    the bounds that were being retrieved were wrong for the Emoji image - causing clipping
> - It was necessary to retrieve the Emoji code point advance via a CoreText API since
>    the HMTX metrics were very wrong - causing overlapping glyphs
> - drawString checks if it is an Emoji run and redirects to a new drawColorGlyph method
>    which draws the image as a texture
> - All 3 rendering pipelines have this support and have been verified on all 3 desktop platforms

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

  8290866

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1047/files
  - new: https://git.openjdk.org/jfx/pull/1047/files/acff6dab..cae5274c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1047&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1047&range=01-02

  Stats: 3 lines in 1 file changed: 0 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1047.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1047/head:pull/1047

PR: https://git.openjdk.org/jfx/pull/1047