Don't truncate the through mode bit in the vertex type during
normalization. Normalization is used to convert different vertex types
to a singular normalized one but the through-mode bit should be preserved.
This only affects (fixes) spline and bezier draw commands. The only thing
that was broken was games that drew splines/beziers with through-mode and
have matricies that differ significantly from the identity (didn't load
identity before drawing).
This should not break anything and fix#5087 .