Previous commit 62579728 fixes a lateral panic issue but does
not handle all the bad cases because it only check if the query
tree contains limit clause. Bad cases for example: if the subquery
is like `q1 union all (q2 limit 1)` then the whole query tree
does not contain limit clause.

Another bad case is the lateral subquery may contain groupby.
like:

    select * from t1_lateral_limit t1 cross join lateral
    (select (c).x+t2.a, sum(t2.a+t2.b) from t2_lateral_limit t2
     group by (c).x+t2.a)x;

When planning the lateraled subquery we do not know where is
the param in the subquery's query tree. Thus it is a bit complicated
to precisely and efficiently resolve this issue.

This commit adopts a simple method to fix panic issue: it justs
check the subquery's query tree to see if there is any group-by
or limit clause, if so, force gather each relation and materialize
them. This is not the best plan we might get. But let's make it
correct first and I think in future we should seriously consider
how to fully and efficiently support lateral.