RFR: 8351867: No UI changes while iconified [v3]

[John Hendrikx]

> Adds code to trigger a scene update when a Window is restored
> 
> This seems to solve https://bugs.openjdk.org/browse/JDK-8351867 and https://bugs.openjdk.org/browse/JDK-8146479

John Hendrikx has updated the pull request incrementally with two additional commits since the last revision:

 - Also call entireSceneNeedsRepaint
 - Add test case

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1733/files
  - new: https://git.openjdk.org/jfx/pull/1733/files/df83df1b..2539511b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1733&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1733&range=01-02

  Stats: 126 lines in 2 files changed: 126 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1733.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1733/head:pull/1733

PR: https://git.openjdk.org/jfx/pull/1733