Duke3D/Engine: TROR Water sectors with an upper sector height of 12144 or less causes clipping problems

If one constructs a TROR water sector where the upper sector (with lotag 1) has a height of 12144 or less, the player is constantly pushed into a single direction, which may even cause him to be crushed. Note that this does not occur with normal non-TROR lotag 1 sectors, and it also does not occur if the upper sector of a TROR area has a solid floor.

This was caused by r7829 (commit 4c9e2706).

Test map to reproduce: aquarium_TRORbug.map