Fix a memory access violation triggeed by a fuzzed binary.

Fix a memory access violation triggeed by a fuzzed binary.

	PR binutils/17512
	* format.c (bfd_check_format_matches): Check for a matching vector
	before using match priorities.
	* mach-o.c (bfd_mach_o_canonicalize_one_reloc): Fix off-by-one
	errors with previous delta.