RFR: 8310638: Filtering a TableView with a large number of items freezes the UI [v2]

[Johan Vos]

> This PR fix a performance issue introduced by the fix for JDK-8306447. In that PR, we changed the behavior in case the cellcount changes. In case the cellcount changes to a lower value than the original one, we have to make sure the current index is not higher than the new amount of cells as that would lead to unnecessary computations.
> 
> Fix for JDK-8310638

Johan Vos has updated the pull request incrementally with one additional commit since the last revision:

  change access to package scope

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1163/files
  - new: https://git.openjdk.org/jfx/pull/1163/files/eea57362..6b4ed092

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1163&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1163&range=00-01

  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1163.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1163/head:pull/1163

PR: https://git.openjdk.org/jfx/pull/1163