D3D9 state cache cleanup

[hrydgard]

Trying to move some stuff on top of thin3d in a separate branch (stencil upload, other future effects), and running into various annoyances. So let's fix them separately.

I think this is safe enough, there really isn't anything complex in here, and the D3D9 backend seems to work just fine.

(Yeah yeah, I should just get around to doing the release at this point...)

[unknownbrackets]

This was done in other backends too, and never changed in D3D9. I think the issue was about order of state processing - by the time it got here, it'd already applied state, so if you changed state here it would break the actual draw. The order of operations may be different now.

-[Unknown]

[unknownbrackets]

I wonder if GPU_DX9::ReapplyGfxState() is needed anymore, then? Really, ideally everything should be based on the state desired when the draw is being constructed. I know when we changed the order of things for Vulkan or GL or something not that long ago, it broke some things and we had to make it careful.

My feeling is that we should merge this right after the next release.

-[Unknown]

[hrydgard]

I will remove GPU_DX9::ReapplyGfxState() , and the ugly stuff in Shade(), in an additional PR after this, for easier user-bisection.

I'll start merging post-1.13 stuff tomorrow unless something big comes up.