Add GE_CMD_COLORTEST to DirtyUniform(DIRTY_ALPHACOLORREF)

This corresponds to 

	if (u_alphacolorref != -1 && (dirtyUniforms & DIRTY_ALPHACOLORREF)) {
		SetColorUniform3Alpha(u_alphacolorref, gstate.colortest, (gstate.alphatest >> 8) & 0xFF);



@hrydgard  , do we need if (diff) before shaderManager_->DirtyUniform(DIRTY_ALPHACOLORREF); ?