Attempt to fix unstable Result Cache regression tests

force_parallel_mode = regress is causing a few more problems than I
thought.  It seems that both the leader and the single worker can
contribute to the execution. I had mistakenly thought that only the worker
process would do any work.  Since it's not deterministic as to which
of the two processes will get a chance to work on the plan, it seems just
better to disable force_parallel_mode for these tests.  At least doing
this seems better than changing to EXPLAIN only rather than EXPLAIN
ANALYZE.

Additionally, I overlooked the fact that the number of executions of the
sub-plan below a Result Cache will execute a varying number of times
depending on cache eviction.  32-bit machines will use less memory and
evict fewer tuples from the cache.  That results in the subnode being
executed fewer times on 32-bit machines.  Let's just blank out the number
of loops in each node.

src/test/regress/expected/resultcache.out

@@ -23,6 +23,7 @@ begin
         ln := regexp_replace(ln, 'Evictions: \d+', 'Evictions: N');
         ln := regexp_replace(ln, 'Memory Usage: \d+', 'Memory Usage: N');
 	ln := regexp_replace(ln, 'Heap Fetches: \d+', 'Heap Fetches: N');
+	ln := regexp_replace(ln, 'loops=\d+', 'loops=N');
         return next ln;
     end loop;
 end;
@@ -30,21 +31,24 @@ $$;
 -- Ensure we get a result cache on the inner side of the nested loop
 SET enable_hashjoin TO off;
 SET enable_bitmapscan TO off;
+-- force_parallel_mode = regress can cause some instability in EXPLAIN ANALYZE
+-- output, so let's ensure that we turn it off.
+SET force_parallel_mode TO off;
 SELECT explain_resultcache('
 SELECT COUNT(*),AVG(t1.unique1) FROM tenk1 t1
 INNER JOIN tenk1 t2 ON t1.unique1 = t2.twenty
 WHERE t2.unique1 < 1000;', false);
-                                    explain_resultcache                                     
---------------------------------------------------------------------------------------------
- Aggregate (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=1000 loops=1)
-         ->  Seq Scan on tenk1 t2 (actual rows=1000 loops=1)
+                                    explain_resultcache                                    
+-------------------------------------------------------------------------------------------
+ Aggregate (actual rows=1 loops=N)
+   ->  Nested Loop (actual rows=1000 loops=N)
+         ->  Seq Scan on tenk1 t2 (actual rows=1000 loops=N)
                Filter: (unique1 < 1000)
                Rows Removed by Filter: 9000
-         ->  Result Cache (actual rows=1 loops=1000)
+         ->  Result Cache (actual rows=1 loops=N)
                Cache Key: t2.twenty
                Hits: 980  Misses: 20  Evictions: Zero  Overflows: 0  Memory Usage: NkB
-               ->  Index Only Scan using tenk1_unique1 on tenk1 t1 (actual rows=1 loops=20)
+               ->  Index Only Scan using tenk1_unique1 on tenk1 t1 (actual rows=1 loops=N)
                      Index Cond: (unique1 = t2.twenty)
                      Heap Fetches: N
 (11 rows)
@@ -63,17 +67,17 @@ SELECT explain_resultcache('
 SELECT COUNT(*),AVG(t2.unique1) FROM tenk1 t1,
 LATERAL (SELECT t2.unique1 FROM tenk1 t2 WHERE t1.twenty = t2.unique1) t2
 WHERE t1.unique1 < 1000;', false);
-                                    explain_resultcache                                     
---------------------------------------------------------------------------------------------
- Aggregate (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=1000 loops=1)
-         ->  Seq Scan on tenk1 t1 (actual rows=1000 loops=1)
+                                    explain_resultcache                                    
+-------------------------------------------------------------------------------------------
+ Aggregate (actual rows=1 loops=N)
+   ->  Nested Loop (actual rows=1000 loops=N)
+         ->  Seq Scan on tenk1 t1 (actual rows=1000 loops=N)
                Filter: (unique1 < 1000)
                Rows Removed by Filter: 9000
-         ->  Result Cache (actual rows=1 loops=1000)
+         ->  Result Cache (actual rows=1 loops=N)
                Cache Key: t1.twenty
                Hits: 980  Misses: 20  Evictions: Zero  Overflows: 0  Memory Usage: NkB
-               ->  Index Only Scan using tenk1_unique1 on tenk1 t2 (actual rows=1 loops=20)
+               ->  Index Only Scan using tenk1_unique1 on tenk1 t2 (actual rows=1 loops=N)
                      Index Cond: (unique1 = t1.twenty)
                      Heap Fetches: N
 (11 rows)
@@ -97,23 +101,24 @@ SELECT explain_resultcache('
 SELECT COUNT(*),AVG(t1.unique1) FROM tenk1 t1
 INNER JOIN tenk1 t2 ON t1.unique1 = t2.thousand
 WHERE t2.unique1 < 1200;', true);
-                                     explain_resultcache                                      
-----------------------------------------------------------------------------------------------
- Aggregate (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=1200 loops=1)
-         ->  Seq Scan on tenk1 t2 (actual rows=1200 loops=1)
+                                    explain_resultcache                                    
+-------------------------------------------------------------------------------------------
+ Aggregate (actual rows=1 loops=N)
+   ->  Nested Loop (actual rows=1200 loops=N)
+         ->  Seq Scan on tenk1 t2 (actual rows=1200 loops=N)
                Filter: (unique1 < 1200)
                Rows Removed by Filter: 8800
-         ->  Result Cache (actual rows=1 loops=1200)
+         ->  Result Cache (actual rows=1 loops=N)
                Cache Key: t2.thousand
                Hits: N  Misses: N  Evictions: N  Overflows: 0  Memory Usage: NkB
-               ->  Index Only Scan using tenk1_unique1 on tenk1 t1 (actual rows=1 loops=1028)
+               ->  Index Only Scan using tenk1_unique1 on tenk1 t1 (actual rows=1 loops=N)
                      Index Cond: (unique1 = t2.thousand)
                      Heap Fetches: N
 (11 rows)
 
 RESET enable_mergejoin;
 RESET work_mem;
+RESET force_parallel_mode;
 RESET enable_bitmapscan;
 RESET enable_hashjoin;
 -- Test parallel plans with Result Cache.

src/test/regress/sql/resultcache.sql

@@ -24,6 +24,7 @@ begin
         ln := regexp_replace(ln, 'Evictions: \d+', 'Evictions: N');
         ln := regexp_replace(ln, 'Memory Usage: \d+', 'Memory Usage: N');
 	ln := regexp_replace(ln, 'Heap Fetches: \d+', 'Heap Fetches: N');
+	ln := regexp_replace(ln, 'loops=\d+', 'loops=N');
         return next ln;
     end loop;
 end;
@@ -32,6 +33,9 @@ $$;
 -- Ensure we get a result cache on the inner side of the nested loop
 SET enable_hashjoin TO off;
 SET enable_bitmapscan TO off;
+-- force_parallel_mode = regress can cause some instability in EXPLAIN ANALYZE
+-- output, so let's ensure that we turn it off.
+SET force_parallel_mode TO off;
 SELECT explain_resultcache('
 SELECT COUNT(*),AVG(t1.unique1) FROM tenk1 t1
 INNER JOIN tenk1 t2 ON t1.unique1 = t2.twenty
@@ -65,6 +69,7 @@ INNER JOIN tenk1 t2 ON t1.unique1 = t2.thousand
 WHERE t2.unique1 < 1200;', true);
 RESET enable_mergejoin;
 RESET work_mem;
+RESET force_parallel_mode;
 RESET enable_bitmapscan;
 RESET enable_hashjoin;