IPA ICF: fix memory leak.

gcc/ChangeLog:

2014-11-25  Martin Liska  <mliska@suse.cz>
	    David Malcolm  <dmalcolm@redhat.com>

	* ipa-icf.c (sem_function::equals_private): int* is replaced with
	auto_vec.
	(sem_function::bb_dict_test): Likewise.
	* ipa-icf.h: Likewise.