Wrong query result while using some value filter + limit

To replay, using the following sqls:

```
insert into root.db.d1(time, s1, s2) aligned values(now(), 1, 1);
insert into root.db.d1(time, s1, s2) aligned values(now(), 2, 2);
insert into root.db.d1(time, s1, s2) aligned values(now(), 3, 3);
insert into root.db.d1(time, s1, s2) aligned values(now(), 4, 40);
insert into root.db.d1(time, s1, s2) aligned values(now(), 5, 50);
insert into root.db.d1(time, s1, s2) aligned values(now(), 6, 60);
select s1, s2 from root.db.d1 where s1 != s2 limit 1;
```

we expect to get the line `4, 40`, but in current version, we got empty result set which is wrong.