Gasoline comes out of the ground so it would not really be a bad thing to dump the old gasoline onto the ground.
Gasoline has leaked onto the ground from cars and vehicles with gas leaks and accidental spillage so there's really no harm in dumping a bit of old gasoline onto the ground if you have no other way of disposing of it.
You could dump the old gasoline on some weeds which I've heard helps to kill weeds or use it to safely start a fire with.
However if you can find a place to safely dispose of the old gasoline then you should take the gasoline to the pace for recycling and proper disposal.
Some counties and towns have recycling programs for gasoline and other hazardous waste where you can freely drop the old gasoline off at.