Fix aim prediction for non-hitscan weapons

lastvisorigin is suppose to be from previous frame, but was always the current origin.
This cause errors trying to get direction enemy is moving in BotAimAtEnemy.

Incorrect lastvisorigin cuased other things to misbehave as well.
Make aas_entityinfo_t use angles from last bot AI entity update

I don't know if this was causing any problems.
Remove old_origin from aas_entityinfo_t

It was unused.