RFR: 8189354: ArrayIndexOutOfBoundsException when listening to selection changes on TreeTableView [v4]

[Kevin Rushforth]

On Sun, 25 Apr 2021 21:40:00 GMT, mstr2 <github.com+43553916+mstr2 at openjdk.org> wrote:

>> This PR fixes the implementation of `ControlUtils.reducingChange`, which incorrectly computed adjacent removed indices, thus resulting in incorrect removal notifications.
>> 
>> Since there were no unit tests for this method, I also added a bunch of tests.
>> 
>> After applying this fix, I can no longer reproduce [JDK-8189354](https://bugs.openjdk.java.net/browse/JDK-8189354) and [JDK-8189228](https://bugs.openjdk.java.net/browse/JDK-8189228).
>
> mstr2 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added test

I reread the description of [JDK-8189228](https://bugs.openjdk.java.net/browse/JDK-8189228) and it describes multiple problems. Are all of them addressed by this PR? If so, then both JBS issues should be closed as part of this PR. One more option for doing so would be to close [JDK-8189354](https://bugs.openjdk.java.net/browse/JDK-8189354) as a duplicate of [JDK-8189228](https://bugs.openjdk.java.net/browse/JDK-8189228), since the AIOOBE is one of the multiple problems described in the latter bug.

If only some of the issues described in [JDK-8189228](https://bugs.openjdk.java.net/browse/JDK-8189228) are fixed by this PR (meaning this PR doesn't really address the larger problem described in JDK-8189228), then that issue should remain open, and a comment added to JDK-8189228 that the fix for [JDK-8189354](https://bugs.openjdk.java.net/browse/JDK-8189354) addresses some of the problems.

@arapte has agreed to be the primary reviewer for this, and can make the call as to which way to proceed regarding those two JBS bugs.

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PR: https://git.openjdk.java.net/jfx/pull/480