Fix window size in X11 when window manager refuses to resize

(cherry picked from commit a67ae8eed5)

src/video/x11/SDL_x11window.c

@@ -979,6 +979,10 @@ void X11_SetWindowSize(_THIS, SDL_Window *window)
         }
 
         if (SDL_TICKS_PASSED(SDL_GetTicks(), timeout)) {
+            /* Timeout occurred and window size didn't change
+             * wwindow manager likely denied the resize. */
+            window->w = orig_w;
+            window->h = orig_h;
             break;
         }