RFR: 8354943: [Linux] Simplify and update glass gtk backend: window sizing, positioning, and state management issues [v50]

[Kevin Rushforth]

On Thu, 14 Aug 2025 15:37:43 GMT, Martin Fox <mfox at openjdk.org> wrote:

>> Just remove the assumeTrue call here. I'll submit the fix for JDK-8364547 in the next day or so and then these system tests will just work.
>
> BTW, it's both the minSize and maxSize tests that are failing on both Mac and Windows. It's really just easier to fix these bugs in advance of submitting this system test.

I'm still seeing failures on macOS in both the min and max tests with `StageStyle.EXTENDED` when I test using this PR + PR #1870 

Without PR 1870, I get 8 failures -- min and max for EXTENDED and min only for the other 4 styles. With PR 1870, I only get the 4 EXTENDED stage style (min and max).

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PR Review Comment: https://git.openjdk.org/jfx/pull/1789#discussion_r2433887375