Fix incorrect printing of queries with duplicated join names.

Given a query in which multiple JOIN nodes used the same alias
(which'd necessarily be in different sub-SELECTs), ruleutils.c
would assign the JOIN nodes distinct aliases for clarity ...
but then it forgot to print the modified aliases when dumping
the JOIN nodes themselves.  This results in a dump/reload hazard
for views, because the emitted query is flat-out incorrect:
Vars will be printed with table names that have no referent.

This has been wrong for a long time, so back-patch to all supported
branches.

Philip Dubé

Discussion: https://postgr.es/m/CY4PR2101MB080246F2955FF58A6ED1FEAC98140@CY4PR2101MB0802.namprd21.prod.outlook.com

src/test/regress/sql/create_view.sql

@@ -319,6 +319,15 @@ ALTER TABLE tmp1 RENAME TO tx1;
 \d+ aliased_view_3
 \d+ aliased_view_4
 
+-- Test aliasing of joins
+
+create view view_of_joins as
+select * from
+  (select * from (tbl1 cross join tbl2) same) ss,
+  (tbl3 cross join tbl4) same;
+
+\d+ view_of_joins
+
 -- Test view decompilation in the face of column addition/deletion/renaming
 
 create table tt2 (a int, b int, c int);