RFR: 8366844: Update and automate MouseDraggedOriginatedByScrollBarTest.java [v7]

[Alexey Ivanov]

On Tue, 9 Sep 2025 22:47:47 GMT, Damon Nguyen <dnguyen at openjdk.org> wrote:

>> When testing jtreg manual tests, some tests were out of date. This PR is an attempt at updating the test and automating it. 
>> 
>> `MouseDraggedOriginatedByScrollBarTest.java` works as expected when compared to native apps and outputs drag events even when the mouse pointer is dragged off of the scrollbar and window altogether. Events should still fire, but the previous instructions may make this confusing since it reads as if no events should be output to the textarea at all.
>
> Damon Nguyen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove redundant toString and volatile. Add EDT.

Marked as reviewed by aivanov (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/26636#pullrequestreview-3213050050