generic: mread past eof shows nonzero contents

Certain sequences of generic/127 invocations complain about being
able to mread nonzero contents past eof.  Replicate that here as a
regression test.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
3 files changed