zdtm: Add suid flag to binfmt_misc test

This fixes the following test error:

    FAIL: binfmt_misc.c:111: mount failed (errno = 1 (Operation not permitted))

CRIU tests (./test/zdtm.py run -a) passed.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm/live/static/binfmt_misc.desc

-{'flavor': 'ns', 'flags': 'excl'}
+{'flavor': 'ns', 'flags': 'excl suid'}