re PR sanitizer/64981 (-fsanitize=address cant expand __builtin_ia32_rdtsc)

	PR sanitizer/64981
	* builtins.c (expand_builtin): Call targetm.expand_builtin
	for BUILT_IN_MD builtins regardless of asan_intercepted_p.

	* gcc.dg/asan/pr64981.c: New test.

From-SVN: r220551