xfs: test log recovery checksum with different log buf sizes

xfs: test log recovery checksum with different log buf sizes

XFS had a bug which lead to spurious checksum failures during
verification of log records during recovery. This occurred when the
filesystem was mounted for recovery with a different log buffer size
(via the 'logbsize=...' mount option from when the filesystem crashed.

Create a regression test that dirties the log using one particular log
buffer size, shuts down the fs and attempts recovery using a larger log
buffer size.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>