RFR: 8347392: Thread-unsafe implementation of c.s.j.scene.control.skin.Utils

[Andy Goryachev]

Thread-safe and re-entrant implementation of Utils.

The new code still uses the static instances of Text and TextLayout for performance reasons, but adds a thread-safe mechanism to keep track of whether any of the instances is in use and when that happens, supplies a new instance instead.  This solves both thread safety and re-entrancy.

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Commit messages:
 - Merge remote-tracking branch 'origin/master' into 8347392.thread.safe.utils
 - 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
 - more jitter
 - disabled titled pane test
 - Merge branch '8348423.node.thread.safety' into 8347392.thread.safe.utils
 - Merge remote-tracking branch 'origin/master' into 8348423.node.thread.safety
 - skip tests
 - ... and 12 more: https://git.openjdk.org/jfx/compare/d615fdc7...203f8de6

Changes: https://git.openjdk.org/jfx/pull/1691/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1691&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347392
  Stats: 349 lines in 2 files changed: 144 ins; 85 del; 120 mod
  Patch: https://git.openjdk.org/jfx/pull/1691.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1691/head:pull/1691

PR: https://git.openjdk.org/jfx/pull/1691