DF-3049 run log (baseline, decisive runs)

$ python3 craft.py df3049.img
gcount = 64 bcount = 524289
group 57 zero-padded (in-bounds-only) csum = 0x04e5
OK wrote df3049.img

guest:
$ /root/vntool attach 0 /root/df3049.img
attached /root/df3049.img size=0
$ mount -t ext2fs -o ro /dev/vn0 /mnt/e2 ; echo RC-A=$?
mount_ext2fs: /dev/vn0: Input/output error
RC-A=71
$ /root/vntool detach 0
$ /root/vntool attach 0 /root/df3049.img
$ newfs /dev/vn1 >/dev/null 2>&1 ; mount /dev/vn1 /mnt/churn && umount /mnt/churn
$ mount -t ext2fs -o ro /dev/vn0 /mnt/e2 ; echo RC-B=$?
mount_ext2fs: /dev/vn0: Input/output error
RC-B=71
$ /root/vntool detach 0
$ /root/vntool attach 0 /root/df3049.img
$ mount -t ext2fs -o ro /dev/vn0 /mnt/e2 ; echo RC-C=$?
mount_ext2fs: /dev/vn0: Input/output error
RC-C=71

console (serial) during the three attempts: see console_lines.txt
  bad gd=57 ... expected=0x7c2e   (A)
  bad gd=63 ... expected=0x58ac   (B)
  bad gd=57 ... expected=0x3c11   (C)