qemu-img: Killed by SIGTRAP on check of the fuzzed image

'qemu-img check -r all' was killed by SIGTRAP.

Sequence:
 1. Unpack the attached archive, make a copy of test.img
 2. Put copy.img and backing_img.qed in the same directory
 3. Execute

qemu-img check -f qcow2 -r all copy.img

Result: qemu-img was killed by SIGTRAP with the reason:

(process:2210): GLib-ERROR **: gmem.c:140: failed to allocate 18446744069633940288 bytes

The qemu-img execution log can be found in the attached archive.

qemu.git HEAD 2d591ce2aeebf