Fix further hash table order dependent tests.

Similar to 0137caf273, this makes contrib and pl tests less dependant on
hash-table order.  After this commit, at least some order affecting
changes to execGrouping.c don't result in regression test changes
anymore.

contrib/test_decoding/expected/ddl.out

@@ -274,9 +274,9 @@ INSERT INTO tr_etoomuch (id, data)
 SELECT g.i, -g.i FROM generate_series(8000, 12000) g(i)
 ON CONFLICT(id) DO UPDATE SET data = EXCLUDED.data;
 SELECT substring(data, 1, 29), count(*)
-FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1')
+FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1') WITH ORDINALITY
 GROUP BY 1
-ORDER BY min(location - '0/0');
+ORDER BY min(ordinality);
            substring           | count 
 -------------------------------+-------
  BEGIN                         |     1

contrib/test_decoding/sql/ddl.sql

@@ -146,9 +146,9 @@ SELECT g.i, -g.i FROM generate_series(8000, 12000) g(i)
 ON CONFLICT(id) DO UPDATE SET data = EXCLUDED.data;
 
 SELECT substring(data, 1, 29), count(*)
-FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1')
+FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1') WITH ORDINALITY
 GROUP BY 1
-ORDER BY min(location - '0/0');
+ORDER BY min(ordinality);
 
 /*
  * check whether we decode subtransactions correctly in relation with each

src/pl/plpython/expected/plpython_spi.out

@@ -220,8 +220,8 @@ SELECT result_len_test($$UPDATE foo3 SET b= '' WHERE a = 2$$);
 
 CREATE FUNCTION result_subscript_test() RETURNS void
 AS $$
-result = plpy.execute("SELECT 1 AS c UNION SELECT 2 "
-                      "UNION SELECT 3 UNION SELECT 4")
+result = plpy.execute("SELECT 1 AS c UNION ALL SELECT 2 "
+                      "UNION ALL SELECT 3 UNION ALL SELECT 4")
 
 plpy.info(result[1]['c'])
 plpy.info(result[-1]['c'])

src/pl/plpython/sql/plpython_spi.sql

@@ -135,8 +135,8 @@ SELECT result_len_test($$UPDATE foo3 SET b= '' WHERE a = 2$$);
 
 CREATE FUNCTION result_subscript_test() RETURNS void
 AS $$
-result = plpy.execute("SELECT 1 AS c UNION SELECT 2 "
-                      "UNION SELECT 3 UNION SELECT 4")
+result = plpy.execute("SELECT 1 AS c UNION ALL SELECT 2 "
+                      "UNION ALL SELECT 3 UNION ALL SELECT 4")
 
 plpy.info(result[1]['c'])
 plpy.info(result[-1]['c'])