ULTIMA8: Difficulty using stairs in Daemon's Crag houses

[OMGPizzaGuy]

Version 2.8.0

In Acolyte Bane's house and the First Acolytes house, the stairs lack a support
block between the visible step and the floor above.
Current position support code will treat walking from the stair to the floor above as unsupported and the player will often slip in the process. This does not break the area entirely, but makes movement around these stairs difficult.

Increasing the Z center support allowed distance to 16 fixes this issue, but allow bad positioning in other places like Central Tenebrae

[OMGPizzaGuy]

Here's an attempt fix questionable results: ​https://github.com/OMGPizzaGuy/scummvm/tree/u8-gap-support

This attempted to check support across a gap, but makes it difficult to go down some stairs in Central Tenebrae. It might be better to handle this as an edge case in the animation tracker