Fixed bugs: mdev-13780 CTE not found, mdev-14184 recursive CTE not found

The support of embedded CTEs was not correct in the cases when
embedded CTEs were used multiple times. The problems occurred with
both non-recursive (bug mdev-13780) and recursive (bug mdev-14184)
embedded CTEs.

mysql-test/r/cte_recursive.result

@@ -2875,3 +2875,25 @@ f
 2
 set standard_compliant_cte=default;
 DROP TABLE t;
+#
+# mdev-14184: recursive CTE embedded into CTE with multiple references 
+#
+WITH
+cte1 AS (
+SELECT n FROM (
+WITH RECURSIVE rec_cte(n) AS (
+SELECT 1 as n1
+UNION ALL
+SELECT n+1 as n2 FROM rec_cte WHERE n < 3
+) SELECT n FROM rec_cte
+) AS X
+),
+cte2 as (
+SELECT 2 FROM cte1
+)
+SELECT *
+FROM cte1;
+n
+1
+2
+3