RFR: 8348423: [TestBug] stress test Nodes initialization from a background thread [v9]

[Andy Goryachev]

> Created a test that validates various Nodes can be initialized in a background thread.

Andy Goryachev 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 15 additional commits since the last revision:

 - review comments
 - Merge remote-tracking branch 'origin/master' into 8348423.node.thread.safety
 - more jitter
 - Merge remote-tracking branch 'origin/master' into 8348423.node.thread.safety
 - skip tests
 - jiggler
 - better name
 - fast loop
 - review comments
 - cleanup
 - ... and 5 more: https://git.openjdk.org/jfx/compare/27dbf5ce...0078aa18

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1690/files
  - new: https://git.openjdk.org/jfx/pull/1690/files/30700a69..0078aa18

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1690&range=08
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1690&range=07-08

  Stats: 1447 lines in 19 files changed: 1248 ins; 148 del; 51 mod
  Patch: https://git.openjdk.org/jfx/pull/1690.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1690/head:pull/1690

PR: https://git.openjdk.org/jfx/pull/1690