git: openjdk/jfx-sandbox: glass_gtk_bug_squashing: Add tests

[duke]

Changeset: fb612eb9
Branch: glass_gtk_bug_squashing
Author:    Thiago Milczarek Sayao <thiago.sayao at gmail.com>
Date:      2025-04-06 19:19:39 +0000
URL:       https://git.openjdk.org/jfx-sandbox/commit/fb612eb9aa3d457e65dfe832777cad0b874f0add

Add tests

! modules/javafx.graphics/src/main/native-glass/gtk/glass_window.cpp
! tests/system/src/test/java/test/javafx/stage/RestoreStageTest.java
+ tests/system/src/test/java/test/javafx/stage/StagePropertiesRetentionTest.java
! tests/system/src/test/java/test/robot/javafx/stage/StageAttributesTest.java