iotests/222: fix pylint and mypy complains

iotests/222: fix pylint and mypy complains

Here:
 - long line
 - move to new interface of vm.qmp() (direct passing dict), to avoid
   mypy false-positive, as it thinks that unpacked dict is a positional
   argument.
 - extra parenthesis
 - handle event_wait possible None value

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210824083856.17408-27-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>