core: Unsets the "variable updated" flag at the intended time
This unsets the flag stating some variable got updated when getting the new values and not when checking the flag, as stated in the documentation of RETRO_ENVIRONMENT_GET_VARIABLE_UPDATE.
This unsets the flag stating some variable got updated when getting the new values and not when checking the flag, as stated in the documentation of RETRO_ENVIRONMENT_GET_VARIABLE_UPDATE.