Duke3D: fix actors on lotag 1 sectors not being squishable

Squishing is now prevented if SE7 is present (as previously intended), or when the actor is standing on submergible TROR water.

Here's a map to test it -- based on Faces of Death. The teleporters take you to 3 variants of the water -- without TROR and SE7, one with SE7, and one with TROR: water_crusher_unsloped.map

In Issue 283 I mentioned that there's a small chance that some maps may have used this behavior for progression.

However, on second thought it seems rather unlikely, since I can't imagine someone would have been crazy enough to exploit this for a map, and there haven't been that many maps since 2016.