Prevent platform-dependent output row ordering in a new test query.

Buildfarm indicates this is necessary.

src/test/regress/expected/rowsecurity.out

@@ -2899,12 +2899,14 @@ SELECT row_security_active('current_check');
  f
 (1 row)
 
-SELECT most_common_vals FROM pg_stats where tablename = 'current_check';
-  most_common_vals   
----------------------
- 
- 
- {rls_regress_user1}
+SELECT attname, most_common_vals FROM pg_stats
+  WHERE tablename = 'current_check'
+  ORDER BY 1;
+  attname  |  most_common_vals   
+-----------+---------------------
+ currentid | 
+ payload   | 
+ rlsuser   | {rls_regress_user1}
 (3 rows)
 
 SET SESSION AUTHORIZATION rls_regress_user1;
@@ -2915,9 +2917,11 @@ SELECT row_security_active('current_check');
  t
 (1 row)
 
-SELECT most_common_vals FROM pg_stats where tablename = 'current_check';
- most_common_vals 
-------------------
+SELECT attname, most_common_vals FROM pg_stats
+  WHERE tablename = 'current_check'
+  ORDER BY 1;
+ attname | most_common_vals 
+---------+------------------
 (0 rows)
 
 --

src/test/regress/sql/rowsecurity.sql

@@ -1197,12 +1197,16 @@ SET SESSION AUTHORIZATION rls_regress_user0;
 ANALYZE current_check;
 -- Stats visible
 SELECT row_security_active('current_check');
-SELECT most_common_vals FROM pg_stats where tablename = 'current_check';
+SELECT attname, most_common_vals FROM pg_stats
+  WHERE tablename = 'current_check'
+  ORDER BY 1;
 
 SET SESSION AUTHORIZATION rls_regress_user1;
 -- Stats not visible
 SELECT row_security_active('current_check');
-SELECT most_common_vals FROM pg_stats where tablename = 'current_check';
+SELECT attname, most_common_vals FROM pg_stats
+  WHERE tablename = 'current_check'
+  ORDER BY 1;
 
 --
 -- Collation support