Ignore out-of-range gid/uid/size/ino and harden AFIO parsing (#2258)

Ignore out-of-range gid/uid/size/ino and harden AFIO parsing (#2258)

The fuzzer constructed an AFIO (CPIO variant) archive that had a
rediculously large ino value, which caused an overflow of a signed
64-bit intermediate.

There are really three issues here:
* The CPIO parser was using a signed int64 as an intermediate type for
parsing numbers in all cases. I've addressed the overflow here by using
a uint64_t in the parser core, but left the resulting values as int64_t.
* The AFIO header parsing had no guards against rediculously large
values; it now rejects an archive when the ino or size fields (which are
allowed to be up to 16 hex digits long) overflow int64_t to produce a
negative value.
* The archive_entry would accept negative values for gid/uid/size/ino.
I've altered those so that these fields treat any negative value as zero
for these fields.

There was one test that actually verified that we could read a field
with size = -1. I've updated that to verify that the resulting size is
zero instead.

OSS-Fuzz Issue: 70019