RFR: 8351867: No UI changes while iconified [v2]

[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 with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'openjdk:master' into feature/minimize-issue
 - Ensure a redraw is performed after windows is restored

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1733/files
  - new: https://git.openjdk.org/jfx/pull/1733/files/f43bbff1..df83df1b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1733&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1733&range=00-01

  Stats: 148937 lines in 832 files changed: 47572 ins; 57104 del; 44261 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