RFR: 8365635: Add MOUSE_DRAG_DONE event type [v4]

[Nir Lisker]

> Adds `MOUSE_DRAG_DONE` event type to `MouseDragEvent` and appropriate handlers.

Nir Lisker has updated the pull request incrementally with one additional commit since the last revision:

  Review comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1873/files
  - new: https://git.openjdk.org/jfx/pull/1873/files/55717111..eb16e369

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1873&range=03
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1873&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1873.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1873/head:pull/1873

PR: https://git.openjdk.org/jfx/pull/1873