Make get_odr_name_for_type check for TYPE_DECL in the way that
its caller warn_types_mismatch previously did.

2019-12-10  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* ipa-utils.h (get_odr_name_for_type): Check for a TYPE_DECL.
	* ipa-devirt.c (warn_types_mismatch): Don't call xstrdup for the
	second demangled name.

gcc/testsuite/
	* gcc.dg/lto/tag-1_0.c, gcc.dg/lto/tag-1_1.c: New test.

From-SVN: r279159