[d3d9] Handling more state-related setters/getters

[WinterSnowfall]

Apparently there are a few games (mostly d3d8) that use Set/GetPaletteEntries and Set/GetCurrentTexturePalette, although, strangely, they do not employ any paletted textures whatsoever...

SetNPatchMode calls are also somewhat common, even though the games do not make use of n patches. It might be the games explicitly disabling it (probably in most cases with few calls), however there are some doing thousands/hundred of thousands of calls 🐸...

GetGPUThreadPriority has no known users, but I've returned 0 for good measure since we D3D_OK it, so it would expect something.

Drafting until I do a bit more testing and investigate potential corner cases around palettes.

[WinterSnowfall]

Should be good to go. The texture palette setters & getters seem to work just fine on XP, even with cards/driver that don't support P8, although they won't do anything useful in that case, of course (and yes, some games still call them, because why not).

I've also piped in D3DRS_PATCHSEGMENTS from D3D8 into Set/GetNPatchMode. Of course there's no documentation around it, but since D3DRS_PATCHSEGMENTS is missing in D3D9, if we ever do get around to adding support for "TruForm", I'm guessing that's needed to get things working properly anyway, since values > 1.0f are what enable n-patches tessellation in both D3D8 and D3D9.