generic: Add nocheck shutdown stress test

generic: Add nocheck shutdown stress test

Most shutdown tests only run on filesystems with metadata
journaling, so we lose coverage. Add a shutdown stress test that
doesn't check for consistency, so does not require journaling. This
is a modified version of generic/051, with some extras trimmed and
fs checking removed.

Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>