fix: closing the simulator no longer makes a destroyed window current

The python task queue was stopped after the windows were destroyed, and
its worker, leaving, released the context of its own window, which was
gone by then: a use after free on every exit. The queue is stopped
first.

application/application.cpp

@@ -717,11 +717,11 @@ void eu07_application::exit()
 
 	ui_layer::shutdown();
 
+	m_taskqueue.exit();
 	for (auto *window : m_windows)
 	{
 		glfwDestroyWindow(window);
 	}
-	m_taskqueue.exit();
 	glfwPollEvents(); // TODO: This fixes a segfault on Wayland when closing. Remove after updating glfw to 3.5.
 	glfwTerminate();