qemu-img: Segfault on a fuzzed image with large values of L1/L2 entries

'qemu-img check -r all/leaks' failed with a segmentation fault on the fuzzed image with L1/L2 entry values having UINT64 border values.

Sequence:
 1. Unpack the attached archive, make a copy of test.img
 2. Put copy.img and backing_img.raw in the same directory
 3. Execute
   
qemu-img check -f qcow2 -r all copy.img

Result: qemu-img was killed by SIGSEGV.

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


qemu.git HEAD 2d591ce2aeebf