Btrfs would get a transaction abortion when remounting RW to RO with
flushoncommit enabled. This test is to check if bug still exists.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>