Water Enablers/Disablers in Corpse fixes

[guwahavel]

1. Using Water Enablers in Corpse will not force the CORPSE3 BackdropType as expected
   

2. Using Water Disablers in Corpse makes the room use the CORPSE3 BackdropType despite the CORPSE1/CORPSE2 backdrops being expected
   

3. The "blood leaking from door" effect in rooms adjacent to blood-flooded rooms in Corpse does not account for Water Enablers/Disablers in the neighboring rooms. This is because this effect likely checks for the RoomDescriptor.FLAG_FLOODED flag, which is what floors like Downpour, Flooded Caves, and Corpse set in rooms on floor entry to automatically flood those rooms when they are entered. Water Enablers also automatically flood layouts on room entry, but the game does not consider these layouts "flooded" when evaluating them from outside the room. This issue is probably a lot harder to fix relative to how noticeable it is and less of a priority than the first two.