block: vhdx qemu-iotest - log replay of data sector

This tests the replay of a data sector in a VHDX image file.

The image file is a 10G dynamic image, with 4MB block size.  The
image was created with qemu-img, and the log left unplayed by
modification of the vhdx image format driver.

It was verified under both QEMU and Hyper-V that the image file,
post log replay, matched.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
