alias.c (get_alias_set): Before checking TYPE_ALIAS_SET_KNOWN_P double check that...

alias.c (get_alias_set): Before checking TYPE_ALIAS_SET_KNOWN_P double check that type is main variant.

	* alias.c (get_alias_set): Before checking TYPE_ALIAS_SET_KNOWN_P
	double check that type is main variant.
	* tree.c (build_variant_type_copy): Clear TYPE_ALIAS_SET when producing
	variant.
	(verify_type_variant): Verify that variants have no
	TYPE_ALIAS_SET_KNOWN_P set
	* tree-streamer-out.c (pack_ts_type_common_value_fields): Reorder
	streaming so constant fields come first; stream TYPE_ALIAS_SET==0
	only for main variants; stream TYPE_ALIAS_SET as a bit.
	* tree-streamer-in.c (unpack_ts_type_common_value_fields): Update
	accordingly.

From-SVN: r230838