RFR: 8245181: TreeTableViewTest > test_rt35039_resetRootChildren logs an exception

[Ajit Ghaisas]

Issue : https://bugs.openjdk.java.net/browse/JDK-8245181

Root cause : The exception just gets logged and does not result in test failure.

Fix : Added the mechanism to catch and handle UncaughtException. Test test_rt35039_resetRootChildren fails with this
mechanism. Fixed the test failure by adding the check in TreeTableView class. In addition, unrelated to above fix, I
have removed System.out.printlns that were causing log pollution.

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Commit messages:
 - fix_8245181

Changes: https://git.openjdk.java.net/jfx/pull/224/files
 Webrev: https://webrevs.openjdk.java.net/jfx/224/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8245181
  Stats: 32 lines in 2 files changed: 24 ins; 6 del; 2 mod
  Patch: https://git.openjdk.java.net/jfx/pull/224.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/224/head:pull/224

PR: https://git.openjdk.java.net/jfx/pull/224