testautomation: create no window, so that testautomation_mouse.c::mouse_getMouseFocus() pass

(more precisely, the last test,  when the window is destroyed, focus window should report null)

test/testautomation.c

@@ -72,6 +72,9 @@ int main(int argc, char *argv[])
         return 1;
     }
 
+    /* No need of windows (or update testautomation_mouse.c:mouse_getMouseFocus() */
+    state->num_windows = 0;
+
     /* Parse commandline */
     for (i = 1; i < argc;) {
         int consumed;