Regression - Most DirectX Games are broken as of recently

As of recently out DirectX stack has seemingly kicked the bucket.
Reproduction steps:
1) Install virtualbox 7.0.6
2) Install latest master on a VM set to windows 2003 as a guest target,
but DO NOT install guest additions as they skew results.
3) Install Mesa SW renderer
3) Download the diablo 2 demo or any other common directx game (Like the WC3 Demo)
4) Try to run and find different types of failures.

Attached below is a log from the assertion I get just from trying to load diablo 2, Warcraft 3 and a picture of the result. and as a control; a screenshot from 0.4.14 running diablo 2 fine with this exact configuration (No guest additions)

Common result is the CPU being at 100% and the game never rendering anything or missing UI elements or outright looking completely incorrect when in game.

All of these things used to work perfectly in master about 6 months ago. Will bisect result when I can.