RFR: 8252936: Optimize removal of listeners from ExpressionHelper.Generic [v2]

[dannygonzalez]

> https://bugs.openjdk.java.net/browse/JDK-8185886
> 
> Optimisation to ExpressionHelper.Generic class to use Sets rather than Arrays to improve listener removal speed.
> 
> This was due to the removal of listeners in TableView taking up to 50% of CPU time on the JavaFX Application thread when scrolling/adding rows to TableViews.
> 
> This may alleviate some of the issues seen here:
> 
> TableView has a horrific performance with many columns #409
> https://github.com/javafxports/openjdk-jfx/issues/409#event-2206515033
> 
> JDK-8088394 : Huge memory consumption in TableView with too many columns
> JDK-8166956: JavaFX TreeTableView slow scroll performance
> JDK-8185887: TableRowSkinBase fails to correctly virtualise cells in horizontal direction
> 
> OpenJFX mailing list thread: TableView slow vertical scrolling with 300+ columns
> https://mail.openjdk.java.net/pipermail/openjfx-dev/2020-January/024780.html

dannygonzalez has updated the pull request incrementally.

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Changes:
  - all: https://git.openjdk.java.net/jfx/pull/108/files
  - new: https://git.openjdk.java.net/jfx/pull/108/files/05c37196..05c37196

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=108&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=108&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/108.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/108/head:pull/108

PR: https://git.openjdk.java.net/jfx/pull/108