vertexjit: Optimize u8/u16 weights a little.

Only for uncommon values.
vertexjit: Initial u8/u16 weights for d3d9.
Oops, forgot to multiply.
vertexjit: Optimize the d3d9 weights a bit.

Only used without skinning on, or with morph, of course.
Fix DX9 bbox crash (DrawEngine::decoded wasn't initialized, because it also existed in the DX9 draw engine)
Move GetCurrentSimpleVertices to DrawEngineCommon
Clean up some indentation
D3D: Specify maxindex correctly in DrawIndexedPrimitive
DX9: Specify max index correctly
Really set maxindex correctly..
Reduce the diff between the two draw engines
More code deduplication. Also normalized some line endings.
vertexjit: Use SSE for all weights, u8/u16.
vertexjit: Use SSE4 in tc u8/u16 code.

It's not much different for non-SSE 4, might as well be common.
Replace download frame in Rezel Cross
Replace download frame in Toaru Majutsu to Kagaku no Ensemble
Another function replace in Kirameki School Life
Replace function in Hentai Ouji To Warawanai Neko
Replace function in Toradora! Portable
Merge pull request #6917 from unknownbrackets/vertexjit

Add x86 weight ToFloat handling for d3d9