Roof surfing

## Testmerges
#9894: 'Multiz indicator' by Detective-Google at commit 5dbc10a0d2
#10340: 'New on_mobs for splints, bandages and blood overlays (Other changes to blood included)' by LC4492 at commit 14a671a4e4
#10830: 'cm-live' by hry-gh at commit 5445fa1183
#9141: 'Shield Code backend rewrite.' by realforest2001 at commit ad8eac6adb
#10895: 'Moves SDTimeAward out of staff ranks.' by realforest2001 at commit c7aee3b53b
#8846: 'Tyrargo Rift - Ground Map' by Steelpoint at commit 010f847f37
#10872: '[RM] Temporary Multi-Z Roof Layer' by thwompa at commit 5e2088577b
#10883: 'Blocks tiles you cannot view while looking up' by Git-Nivrak at commit e83e2d8d9e

## Round ID
30474

## Description of the bug
Lurkers able to "surf roofs" (looks like only in south direction) if they try to diagonal pounce on an inverted corner

## What's the difference with what should have happened?
Roof surfing either stable mechanic or not existing

## How do we reproduce this bug?
1) Find roof with inverted corner
2) Get jumping xeno right next to the corner
3) Jump diagonally on the roof
4)???
5) You're on the other side of the roof, south relative to your previous location

## Attached logs
```
N/A
```

## Additional details
- Author: Kalazus_mine
- Admin: Hermotimos
- Note: None