update SDL soruce to 2.0.14

Edward Rudd

2021-06-15 dec7875a6e23212021e4d9080330a42832dfe02a

 source/test/testtimer.c

@@ -107,7 +107,7 @@
    now = SDL_GetPerformanceCounter();
    SDL_Log("1 million iterations of ticktock took %f ms\n", (double)((now - start)*1000) / SDL_GetPerformanceFrequency());

    SDL_Log("Performance counter frequency: %"SDL_PRIu64"\n", (unsigned long long) SDL_GetPerformanceFrequency());
    SDL_Log("Performance counter frequency: %"SDL_PRIu64"\n", SDL_GetPerformanceFrequency());
    start32 = SDL_GetTicks();
    start = SDL_GetPerformanceCounter();
    SDL_Delay(1000);