* tree.c (free_lang_data_in_type): If BINFO has no important
	information in it, set it to NULL.
	(get_binfo_at_offset): Do not walk fields, only bases.
	* ipa-utils.h (polymorphic_type_binfo_p): Be ready for BINFO_TYPE
	to be NULL.
	* ipa-polymorphic-call.c (record_known_type): Likewise.

From-SVN: r217824