git: openjdk/jfx-sandbox: tsayao_xlib: Fix is_visible()

[duke]

Changeset: c0859d2a
Author:    Thiago M Sayao <thiago.sayao at clamed.com.br>
Date:      2022-02-25 11:50:28 +0000
URL:       https://git.openjdk.java.net/jfx-sandbox/commit/c0859d2a10ec9c42797f03054d75789f62d732f1

Fix is_visible()

! modules/javafx.graphics/src/main/native-glass/gtk/GlassApplication.cpp
! modules/javafx.graphics/src/main/native-glass/gtk/glass_window.cpp
! modules/javafx.graphics/src/main/native-glass/gtk/glass_window.h