RFR: 8301761: The sorting of the SortedList can become invalid [v2]

[Loay Ghreeb]

> Fix an issue in `SortedList` where the sorting became incorrect when adding new items that are equal to existing items according to the comparator. The `SortedList` should consider the insertion index of these items to maintain the correct order.

Loay Ghreeb has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Merge branch 'master' into SortedList
 - Merge branch 'master' into SortedList
 - Merge branch 'master' into SortedList
 - Add test case
 - Fix SortedList to maintain insertion order for equal elements

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1519/files
  - new: https://git.openjdk.org/jfx/pull/1519/files/fa2deb48..15f1a9ab

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1519&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1519&range=00-01

  Stats: 643 lines in 8 files changed: 472 ins; 61 del; 110 mod
  Patch: https://git.openjdk.org/jfx/pull/1519.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1519/head:pull/1519

PR: https://git.openjdk.org/jfx/pull/1519