Support Referring to a CTE in Subsequent CTEs

[reata]

WITH
cte1 AS (SELECT a FROM tab1),
cte2 AS (SELECT a FROM cte1)
INSERT OVERWRITE TABLE tab2
SELECT a FROM cte2

This is valid syntax and yet now we treat CTE as exactly the same as subquery, while subquery cannot reference previously defined subquery. We should add support for this.

Reference: https://stackoverflow.com/questions/27204824/sql-use-a-reference-of-a-cte-to-another-cte