add xwayland unmanaged tests to support dmenu

This adds `wlr_xwayland_surface_is_unamanged`, to allow compositors more
fine grained control over XWayland focus.
A surface that is unmanaged should not receive focus, while other
windows that are just override redirect may want it (dmenu).
The way unamanged is determined is taken from wlc.

rootston/xwayland.c

@@ -350,5 +350,7 @@ void handle_xwayland_surface(struct wl_listener *listener, void *data) {
 		}
 
 		view_setup(view);
+	} else {
+		view_initial_focus(view);
 	}
 }