RFR: 8197991: Selecting many items in a TableView is very slow

[Abhinay Agarwal]

This work improves the performance of `MultipleSelectionModel`  over large data sets by caching some values and avoiding unnecessary calls to `SelectedIndicesList#size`. It further improves the performance by reducing the number of iterations required to find the index of an element in the BitSet.

The work is based on [an abandoned patch](https://github.com/openjdk/jfx/pull/127) submitted by @yososs

There are currently 2 manual tests for this fix.

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Commit messages:
 - Update line ending for SelectTableViewTest
 - Update line ending
 - Add manual tests
 - 8197991: Selecting many items in a TableView is very slow

Changes: https://git.openjdk.java.net/jfx/pull/673/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=673&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8197991
  Stats: 256 lines in 4 files changed: 250 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jfx/pull/673.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/673/head:pull/673

PR: https://git.openjdk.java.net/jfx/pull/673