RFR: 8354813: Parent.isNeedsLayout() may return wrong value in property listener

[Michael Strauß]

A listener that is added to `Parent.needsLayoutProperty()` may see a wrong value when calling `Parent.isNeedsLayout()` from the callback. The fix is to apply the value before notifying the listeners.

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Commit messages:
 - fix
 - failing test

Changes: https://git.openjdk.org/jfx/pull/1781/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1781&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354813
  Stats: 29 lines in 3 files changed: 26 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1781.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1781/head:pull/1781

PR: https://git.openjdk.org/jfx/pull/1781