U464 - picking up items while swallowed in a shop

U464 - picking up items while swallowed in a shop
The bug report referred to greased hands, but that doesn't affect the
behavior.  If you drop an object while swallowed or engulfed in a shop, and
that object had previously been picked up from the shop floor, the object
was treated as costly.  In some cases, this could result in impossible
errors later on.  Perhaps object ox & oy should be modified when in
player/monster inventory, but this fix addresses the specific problem by
not doing the costly check while swallowed.