Fixes review issues

src/backend/distributed/sql/downgrades/citus--12.1-1--12.0-1.sql

@@ -1,5 +1,5 @@
 -- citus--12.1-1--12.0-1
-
+DROP FUNCTION pg_catalog.citus_pause_node_within_txn(int,bool,int);
 -- we have modified the relevant upgrade script to include any_value changes
 -- we don't need to upgrade this downgrade path for any_value changes
 -- since if we are doing a Citus downgrade, not PG downgrade, then it would be no-op.

src/backend/distributed/sql/udfs/citus_pause_node_within_txn/latest.sql

@@ -0,0 +1,13 @@
+CREATE FUNCTION pg_catalog.citus_pause_node_within_txn(node_id int,
+                                              force bool DEFAULT false,
+                                              lock_cooldown int DEFAULT 10000)
+  RETURNS void
+  LANGUAGE C STRICT
+  AS 'MODULE_PATHNAME', $$citus_pause_node_within_txn$$;
+
+COMMENT ON FUNCTION pg_catalog.citus_pause_node_within_txn(node_id int,
+                                              force bool ,
+                                              lock_cooldown int )
+  IS 'pauses node with given id which leads to add lock in tables and prevent any queries to be executed on that node';
+
+REVOKE ALL ON FUNCTION pg_catalog.citus_pause_node_within_txn(int,bool,int) FROM PUBLIC;