alpha-vms: Sanity check ETIR__C_CTL_DFLOC index

alpha-vms: Sanity check ETIR__C_CTL_DFLOC index

I doubt anyone will want to create more than 16M debug location
entries.  If there is no bound the object format allows for 32-bit
indices and of course fuzzers find that and attempt allocation of up
to a 16G byte array.  The patch also fixes potential integer overflows
in calculating the array size.

	* vms-alpha.c (dst_define_location): Limit size of dst_ptr_offsets
	array.
	(_bfd_vms_slurp_object_records): Rename "err" to "ok".