binary/reader: Switch to up-front CRC64ISO validation
In line with the recent WriterToken change, we now check the entire
CRC64ISO up-front from the mmap()'d archive, ensuring we don't try to
load a corrupt file into memory. While this may cause some extra reads
and faults, its essential from a corruption POV.
Signed-off-by: Ikey Doherty <email@example.com>