1. The correlated slot ref should be bound by the agg tuple of outer query.
However, the correlated having clause can not be analyzed correctly so the result is incorrect.
For example:
```
SELECT k1 FROM test GROUP BY k1
HAVING EXISTS(SELECT k1 FROM baseall GROUP BY k1 HAVING SUM(test.k1) = k1);
```
The correlated predicate is not executed.
2. The limit offset should also be rewritten when there is subquery in having clause.
For example:
```
select k1, count(*) cnt from test group by k1 having k1 in
(select k1 from baseall order by k1 limit 2) order by k1 limit 5 offset 3;
```
The new stmt should has a limit element with offset.
07a9401f82