RFR: 8295754: PaginationSkin: memory leak when changing skin

[Andy Goryachev]

Fixes memory leaks as determined by SkinMemoryLeakTest (remove line 171) and a leak tester
https://github.com/andy-goryachev-oracle/Test/blob/main/src/goryachev/apps/LeakTest.java

Make sure to configure the current test in LeakTest:
protected final Type WE_ARE_TESTING = Type.PAGINATION;

Found another issue: Pagination class does not survive replacing its skin (all components disappear).

caused by:
- adding and not removing listeners
- adding and not removing children Nodes
- setting control's properties in the constructor
- incorrectly setting a clip rectangle

NOTE: the fix will requires both ListenerHelper [JDK-8294809](https://bugs.openjdk.org/browse/JDK-8294809) and Skin.install() [JDK-8290844](https://bugs.openjdk.org/browse/JDK-8290844) changes.

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Commit messages:
 - 8295754: cleanup
 - Merge remote-tracking branch 'origin/master' into 8295754.pagination.skin
 - 8295754: review comments
 - Merge remote-tracking branch 'origin/8294809.listener.helper' into 8295754.pagination.skin
 - 8294809: review comments
 - Merge remote-tracking branch 'origin/master' into 8294809.listener.helper
 - 8294809: review comments
 - 8294809: review comments
 - Merge remote-tracking branch 'origin/master' into 8294809.listener.helper
 - 8294809: review comments
 - ... and 65 more: https://git.openjdk.org/jfx/compare/3376228a...c6191da3

Changes: https://git.openjdk.org/jfx/pull/925/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=925&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295754
  Stats: 128 lines in 2 files changed: 56 ins; 44 del; 28 mod
  Patch: https://git.openjdk.org/jfx/pull/925.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/925/head:pull/925

PR: https://git.openjdk.org/jfx/pull/925