PG-186: Add support to monitor query execution plan.

regression/expected/basic.out

@@ -5,12 +5,6 @@ SELECT pg_stat_monitor_reset();
  
 (1 row)
 
-select pg_sleep(.5);
- pg_sleep 
-----------
- 
-(1 row)
-
 SELECT 1 AS num;
  num 
 -----
@@ -18,13 +12,11 @@ SELECT 1 AS num;
 (1 row)
 
 SELECT query FROM pg_stat_monitor ORDER BY query COLLATE "C";
-                             query                             
----------------------------------------------------------------
+              query              
+---------------------------------
  SELECT $1 AS num
  SELECT pg_stat_monitor_reset();
- SELECT query FROM pg_stat_monitor ORDER BY query COLLATE "C";
- select pg_sleep($1)
-(4 rows)
+(2 rows)
 
 SELECT pg_stat_monitor_reset();
  pg_stat_monitor_reset