Don't truncate spline/bezier through mode

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 hrydgard#5087 .

GPU/GLES/Spline.cpp

@@ -124,7 +124,7 @@ u32 TransformDrawEngine::NormalizeVertices(u8 *outPtr, u8 *bufPtr, const u8 *inP
 	}
 
 	// Okay, there we are! Return the new type (but keep the index bits)
-	return GE_VTYPE_TC_FLOAT | GE_VTYPE_COL_8888 | GE_VTYPE_NRM_FLOAT | GE_VTYPE_POS_FLOAT | (vertType & GE_VTYPE_IDX_MASK);
+	return GE_VTYPE_TC_FLOAT | GE_VTYPE_COL_8888 | GE_VTYPE_NRM_FLOAT | GE_VTYPE_POS_FLOAT | (vertType & (GE_VTYPE_IDX_MASK | GE_VTYPE_THROUGH));
 }
 
 u32 TransformDrawEngine::NormalizeVertices(u8 *outPtr, u8 *bufPtr, const u8 *inPtr, int lowerBound, int upperBound, u32 vertType) {