Function test

test/emscripten_performance_now.c:9–18

double dateNow;

void test(void *userData) {
  double now2 = emscripten_performance_now();
  assert(now2 >= performanceNow + 100);

  double now3 = emscripten_date_now();
  assert(now3 >= dateNow + 100);

  printf("done\n");
  exit(0);
}

int main() {
  performanceNow = emscripten_performance_now();