not allowing pathing through shks can cause oscillation

[doy]

In a layout like this (, are unexplored tiles):

                   --------      
                   |......%######
                   |.>....|      
                   |......|      
  ----,           #.......|      
  |[[[,,,       ###--|-.---      
  |)[[[[,,,     @    [#####      
  |)[)[[[[,,, ###      ##########
  |[[[[[[[[[, #           ###   #
  |[mm[)[[[[.-#             #   #
  -----------               ##  #
                    ---------.--#
                    |...........#
                    |...........#
                    |..{........#
                    |..........-#
                    -----------.,
                              ,,,

where the room on the left is a shop and the shk is standing right in the doorway, TAEB will try to path to the mimics, but the shk becomes visible, it will block the pathing, and so TAEB will try to path back into the room on the bottom to see if it can go out the unexplored tiles on the bottom right of that room and all the way out around the left of the shop, and then into the shop from the top where there are also unexplored tiles because the entire shop hasn't been seen yet. We should come up with a more intelligent thing to do in this situation (not sure what yet). Part of the problem is that monsters are only remembered for a short period of time, and so eventually it'll forget that the shk is there and go back to see if the short path is doable again.