Offset is not processed correctly

table `foo` has 6 rows; the query:
```sql
SELECT
FLOOR(__time TO DAY) t,
COUNT(1)
FROM ( select * from foo order by __time offset 3 ) f
group by FLOOR(__time TO DAY)
```
return 6 rows; regardless of the `offset` inside the subq

The issue names no files or tests. Reproduce the SQL query against a six-row table, then trace how OFFSET in the ordered subquery is handled; done means the subquery's offset changes the rows seen by the outer grouping query.

Written by the indexing model from the issue text.