fix U88 - invisible hero didn't sense self via ESP

fix U88 - invisible hero didn't sense self via ESP

     If the character was invisible without being able to see invisible,
his location on the map showed any object there or underlying topology
instead of the hero even when monsters could be seen with infravision,
ESP, or sustained monster detection.  The ESP case required an amulet
or helm or quest artifact to be noticeable because being blind overrides
being unable to see invisible, so the more common form of telepathy
didn't exhibit this behavior.