Remove SDL_GetTicks64() ifdefs

We can now use the function that doesn't wrap after ~49 days since
SDL 2.0.18 released.

desktop_version/src/Script.cpp

@@ -3087,12 +3087,8 @@ void scriptclass::hardreset(void)
 {
     const bool version2_2 = GlitchrunnerMode_less_than_or_equal(Glitchrunner2_2);
 
-#if SDL_VERSION_ATLEAST(2, 0, 17)
     /* The RNG is 32-bit. We don't _really_ need 64-bit... */
     xoshiro_seed((Uint32) SDL_GetTicks64());
-#else
-    xoshiro_seed(SDL_GetTicks());
-#endif
 
     //Game:
     game.hascontrol = true;