RFR: 8349255: TitledPane: exception initializing in a background thread [v2]

[Andy Goryachev]

> ## Root Cause
> 
> Animation was started in the background thread, causing concurrent access.
> 
> ## Solution
> 
> Disable animation if not the fx app thread.

Andy Goryachev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 27 commits:

 - revert
 - Merge remote-tracking branch 'origin/master' into 8349255.thread.safe.titled.pane
 - the fix
 - Merge branch 'master' into 8349255.thread.safe.titled.pane
 - Merge branch 'master' into 8349255.thread.safe.titled.pane
 - get parent
 - Merge branch '8348423.node.thread.safety' into 8347392.thread.safe.utils
 - review comments
 - Merge remote-tracking branch 'origin/master' into 8348423.node.thread.safety
 - Merge branch '8348423.node.thread.safety' into 8347392.thread.safe.utils
 - ... and 17 more: https://git.openjdk.org/jfx/compare/d1f5ea81...2c9740e9

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

Changes: https://git.openjdk.org/jfx/pull/1707/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1707&range=01
  Stats: 24 lines in 2 files changed: 10 ins; 10 del; 4 mod
  Patch: https://git.openjdk.org/jfx/pull/1707.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1707/head:pull/1707

PR: https://git.openjdk.org/jfx/pull/1707