xfs/066: stat the test file, not the directory

xfs/066: stat the test file, not the directory

Ever since commit 7e2a19504 ("ls -l reports different file size
depending on platform and user.") xfs/066 has been running stat on
the dump/restore directory instead of the large file that the test
is checking can be dumped and restored correctly. IOWs, it's not
been checking the correct thing for almost 10 years.

This test fails on CRC enabled filesystems because the shortform
directory entry size is different (an extra byte for the filetype
filed), and this is where tracking down the failure has lead me.

Fix this by using the correct target file, and improve it by dumping
an md5sum of the source and target files to ensure they contain the
same data.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>