RFR: 8365635: Add MOUSE_DRAG_DONE event type [v3]

[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:

  Changed to HTML comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1873/files
  - new: https://git.openjdk.org/jfx/pull/1873/files/cc11d675..55717111

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1873&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1873&range=01-02

  Stats: 19 lines in 3 files changed: 5 ins; 0 del; 14 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