RFR: 8295809: TreeTableViewSkin: memory leak when changing skin

[Andy Goryachev]

as determined by SkinMemoryLeakTest (remove line 180) and a leak tester
https://github.com/andy-goryachev-oracle/Test/blob/main/src/goryachev/apps/LeakTest.java

caused by:
- adding and not removing listeners
- adding and not removing event handlers/filters
- adding and not removing cell factory
- holding unnecessary instance in TreeTableViewSkin.treeTableViewSkin // test-only

NOTES:
1. this fix requires JDK-8294809 ListenerHelper and JDK-8295806 TableViewSkin.
2. there were more memory leaks in this skin than detected by SkinMemoryLeakTest, probably because of cell factory (?).  A manual test using LeakTest shows that there are no memory leaks after a) replacing skin, b) moving the components to a new window, and c) removing all the components from the window.

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Commit messages:
 - Merge remote-tracking branch 'origin/master' into 8295809.tree.table.view.skin
 - Merge branch '8295806.table.view.skin' into 8295809.tree.table.view.skin
 - Merge remote-tracking branch 'origin/master' into
 - Merge branch '8295806.table.view.skin' into 8295809.tree.table.view.skin
 - Merge remote-tracking branch 'origin/master' into
 - 8295809: cleanup
 - Merge branch '8295806.table.view.skin' into 8295809.tree.table.view.skin
 - Merge remote-tracking branch 'origin/master' into
 - 8295809: temporarily disabled some tests
 - 8295809: plugged the leak
 - ... and 24 more: https://git.openjdk.org/jfx/compare/bb98d886...e6e96d62

Changes: https://git.openjdk.org/jfx/pull/931/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=931&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295809
  Stats: 197 lines in 4 files changed: 93 ins; 77 del; 27 mod
  Patch: https://git.openjdk.org/jfx/pull/931.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/931/head:pull/931

PR: https://git.openjdk.org/jfx/pull/931