VideoCommon: cleanup of "components" usage

This "u32 components" is a list of flags which attributes of the vertex loader are present.
We are used to append this variable to lots of vertex generation functions, but some of them don't need it at all.
Remove the ZTP speedup hack. Also remove useless debugging code, and a presumably outdated workaround (which was commented out).

Fixes issue 6875.
Remove vertex streaming hack.

NV has buffer_storage, AMD has pinned memory.
Both are better than that hack which shouldn't ever have been introduced in the first place.
fixup "Remove the ZTP speedup hack"

This fixes revision b49c09c36b67