Pica/VertexShader: Fix a bug caused due to incorrect assumptions of consecutive output register tables.

We now write create a temporary buffer for output registers and copy all of them to the actual output vertex structure after the shader has run. This is technically not necessary, but it's easier to vectorize in the future.

Includes more opcodes to implement in the future.

Previously it wouldn't jump back to the start of the loop code once it reached the end of the block.
Fixes the texture problems in a lot of games.

Involves making asserts use printf instead of the log functions (log functions are asynchronous and, as such, the log won't be printed in time)
As such, the log type argument was removed (printf obviously can't use it, and it's made obsolete by the file and line printing)

Also removed some GEKKO cruft.

Unused OutputVertex attributes were being left un-initialized. The
leftover garbage sometimes decoded as floating-point denormalized
values, causing fallbacks to microcode and massive slowdowns in the rest
of the rasterization pipeline even though the results were unused. By
zeroing the structure we ensure these attributes only contain harmless
zeros.

More specifically, this also fixes crashes by Citra trying to load a src2 register even if the current instruction does not use that.

This allows for proper emulation of the different CMP/LRP/MAD instructions.