Test whether flaky citus_split_shard_by_split_points_negative + cleanup

citus_split_shard_by_split_points_negative has something leftover.
If I run the test two times in a row in my local machine,
I get the following error in the second test run:

```diff
 -- UDF fails where source shard cannot be split further i.e min and max range is equal.
 -- Create a Shard where range cannot be split further
 SELECT isolate_tenant_to_new_shard('table_to_split', 1, shard_transfer_mode => 'block_writes');
- isolate_tenant_to_new_shard
----------------------------------------------------------------------
-                    49761305
-(1 row)
-
+ERROR:  could not open relation with OID 0
+CONTEXT:  while executing command on localhost:57637
 SELECT citus_split_shard_by_split_points(
        49761305,
        ARRAY['-1073741826'],
        ARRAY[:worker_1_node, :worker_2_node]);
-ERROR:  Cannot split shard id "49761305" as min/max range are equal: ('-1905060026', '-1905060026').
+ERROR:  could not find valid entry for shard 49761305
```

We need a resource cleanup here so I added that line.

src/test/regress/expected/citus_split_shard_by_split_points_negative.out

@@ -136,3 +136,33 @@ DETAIL:  drop cascades to table citus_split_shard_by_split_points_negative.range
 drop cascades to table citus_split_shard_by_split_points_negative.table_to_split
 drop cascades to table citus_split_shard_by_split_points_negative.table_to_split_replication_factor_2
 --END : Cleanup
+SELECT public.wait_for_resource_cleanup();
+ wait_for_resource_cleanup
+---------------------------------------------------------------------
+
+(1 row)
+
+SELECT result FROM run_command_on_all_nodes($$SELECT count(*) FROM pg_replication_slots$$);
+ result
+---------------------------------------------------------------------
+ 0
+ 0
+ 0
+(3 rows)
+
+SELECT result FROM run_command_on_all_nodes($$SELECT count(*) FROM pg_publication$$);
+ result
+---------------------------------------------------------------------
+ 0
+ 0
+ 0
+(3 rows)
+
+SELECT result FROM run_command_on_all_nodes($$SELECT count(*) FROM pg_subscription$$);
+ result
+---------------------------------------------------------------------
+ 0
+ 0
+ 0
+(3 rows)
+

src/test/regress/sql/citus_split_shard_by_split_points_negative.sql

@@ -114,3 +114,9 @@ SELECT citus_split_shard_by_split_points(
 \c - postgres - :master_port
 DROP SCHEMA "citus_split_shard_by_split_points_negative" CASCADE;
 --END : Cleanup
+
+SELECT public.wait_for_resource_cleanup();
+
+SELECT result FROM run_command_on_all_nodes($$SELECT count(*) FROM pg_replication_slots$$);
+SELECT result FROM run_command_on_all_nodes($$SELECT count(*) FROM pg_publication$$);
+SELECT result FROM run_command_on_all_nodes($$SELECT count(*) FROM pg_subscription$$);