All other test files are executable. Fix these.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210116134424.82867-5-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>