Always destroy OpenGL context when the window is destroyed

The OpenGL context was only destroyed when the HasNativeWindow flag was set,
as a consequence there was a context leak.
Remove this condition and always destroy the context.

Change-Id: I3e3424e9d6f179171872fdef5c929a5718af0ed5
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

src/plugins/platforms/eglfs/api/qeglfswindow.cpp

@@ -152,11 +152,14 @@ void QEglFSWindow::destroy()
 
 #ifndef QT_NO_OPENGL
         QOpenGLCompositor::destroy();
+#endif
+    }
+
+#ifndef QT_NO_OPENGL
     if (qt_gl_global_share_context() == m_rasterCompositingContext)
         qt_gl_set_global_share_context(nullptr);
     delete m_rasterCompositingContext;
 #endif
-    }
 
     m_flags = { };
 }