Adapt pg_pathman for PG 11.

I kinda lost interest to exorcise a couple of tests further in attempts to make
them pass on all supported versions and just added copies. These are
 * pathman_expressions now differs because planner converts ROW(Const, Const) to
   just Const of record type.
 * Same with pathman_rebuild_updates.

I have removed inclusion of partition_filter.h in pg_compat.h in 9.5 as it
created circular dependency hell. I think it is not worthwhile to fight with it
since the only thing actually needed was error message, which is used in this
single place.

Small typo fix in partitioning_test.py: con2.begin instead of con1.begin.

Finally, run python tests with --failfast and --verbose options.

Author: arssher

expected/pathman_expressions.out

@@ -1,3 +1,9 @@
+/*
+ * -------------------------------------------
+ *  NOTE: This test behaves differenly on < 11 because planner now turns
+ *  Row(Const, Const) into just Const of record type, apparently since 3decd150
+ * -------------------------------------------
+ */
 \set VERBOSITY terse
 SET search_path = 'public';
 CREATE EXTENSION pg_pathman;
@@ -160,42 +166,38 @@ SELECT *, tableoid::REGCLASS FROM test_exprs.composite;
 (3 rows)
 
 EXPLAIN (COSTS OFF) SELECT * FROM test_exprs.composite WHERE (a, b)::test_exprs.composite < (21, 0)::test_exprs.composite;
-                                          QUERY PLAN                                          
-----------------------------------------------------------------------------------------------
+                                     QUERY PLAN                                     
+------------------------------------------------------------------------------------
  Append
    ->  Seq Scan on composite_1
    ->  Seq Scan on composite_2
    ->  Seq Scan on composite_3
-         Filter: (ROW(a, b)::test_exprs.composite < ROW(21, '0'::text)::test_exprs.composite)
+         Filter: (ROW(a, b)::test_exprs.composite < '(21,0)'::test_exprs.composite)
 (5 rows)
 
 EXPLAIN (COSTS OFF) SELECT * FROM test_exprs.composite WHERE (a, b) < (21, 0)::test_exprs.composite;
-                               QUERY PLAN                               
-------------------------------------------------------------------------
+                          QUERY PLAN                          
+--------------------------------------------------------------
  Append
    ->  Seq Scan on composite_1
-         Filter: (ROW(a, b) < ROW(21, '0'::text)::test_exprs.composite)
+         Filter: (ROW(a, b) < '(21,0)'::test_exprs.composite)
    ->  Seq Scan on composite_2
-         Filter: (ROW(a, b) < ROW(21, '0'::text)::test_exprs.composite)
+         Filter: (ROW(a, b) < '(21,0)'::test_exprs.composite)
    ->  Seq Scan on composite_3
-         Filter: (ROW(a, b) < ROW(21, '0'::text)::test_exprs.composite)
+         Filter: (ROW(a, b) < '(21,0)'::test_exprs.composite)
    ->  Seq Scan on composite_4
-         Filter: (ROW(a, b) < ROW(21, '0'::text)::test_exprs.composite)
+         Filter: (ROW(a, b) < '(21,0)'::test_exprs.composite)
 (9 rows)
 
 EXPLAIN (COSTS OFF) SELECT * FROM test_exprs.composite WHERE (a, b)::test_exprs.composite < (21, 0);
-                           QUERY PLAN                           
-----------------------------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Append
    ->  Seq Scan on composite_1
-         Filter: (ROW(a, b)::test_exprs.composite < ROW(21, 0))
    ->  Seq Scan on composite_2
-         Filter: (ROW(a, b)::test_exprs.composite < ROW(21, 0))
    ->  Seq Scan on composite_3
-         Filter: (ROW(a, b)::test_exprs.composite < ROW(21, 0))
-   ->  Seq Scan on composite_4
-         Filter: (ROW(a, b)::test_exprs.composite < ROW(21, 0))
-(9 rows)
+         Filter: (ROW(a, b)::test_exprs.composite < '(21,0)'::record)
+(5 rows)
 
 DROP TABLE test_exprs.composite CASCADE;
 NOTICE:  drop cascades to 5 other objects