Prevent memory access violations when attempting to parse an x86_64 PE binary containing corrupt unwind information.

	PR 22113
incldue	* coff/pe.h (struct pex64_unwind_info): Add a rawUnwindCodesEnd
	field.

bfd	* pei-x86_64.c (pex64_get_unwind_info): Change to a boolean
	function.  Add an end address parameter.  Check access of the data
	pointer to make sure that they do not extend beyond the end
	address.  Return FALSE if any check fails.  Add the end address
	pointer to the ui structure.
	(pex64_xdata_print_uwd_codes): Check accesses of the raw unwind
	codes to make sure that they do not extend beyond the end address
	pointer.  Print an error message and return immediately if any
	check fails.