[jfx17u] RFR: 8284665: First selected item of a TreeItem multiple selection gets removed if new items are constantly added to the TreeTableView

[Johan Vos]

clean backport of 8284665: First selected item of a TreeItem multiple selection gets removed if new items are constantly added to the TreeTableView

Reviewed-by: aghaisas

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Commit messages:
 - 8284665: First selected item of a TreeItem multiple selection gets removed if new items are constantly added to the TreeTableView

Changes: https://git.openjdk.org/jfx17u/pull/85/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx17u&pr=85&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8284665
  Stats: 101 lines in 4 files changed: 99 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx17u/pull/85.diff
  Fetch: git fetch https://git.openjdk.org/jfx17u pull/85/head:pull/85

PR: https://git.openjdk.org/jfx17u/pull/85