Fix metadata sync fails on multi_follower_schedule

src/test/regress/expected/follower_single_node.out

@@ -8,6 +8,7 @@ SET citus.shard_count TO 4;
 SET citus.shard_replication_factor TO 1;
 SET citus.next_shard_id TO 93630500;
 SELECT 1 FROM master_add_node('localhost', :master_port, groupid => 0);
+NOTICE:  localhost:xxxxx is the coordinator and already contains metadata, skipping syncing the metadata
  ?column?
 ---------------------------------------------------------------------
         1

src/test/regress/expected/multi_follower_dml.out

@@ -16,6 +16,7 @@ SELECT create_distributed_table('the_table', 'a');
 (1 row)
 
 SELECT 1 FROM master_add_node('localhost', :master_port, groupid => 0);
+NOTICE:  localhost:xxxxx is the coordinator and already contains metadata, skipping syncing the metadata
  ?column?
 ---------------------------------------------------------------------
         1
@@ -281,11 +282,14 @@ DELETE FROM the_table;
 ERROR:  cannot assign TransactionIds during recovery
 -- DDL is not possible
 TRUNCATE the_table;
-ERROR:  cannot execute TRUNCATE TABLE in a read-only transaction
+ERROR:  cannot acquire lock mode AccessExclusiveLock on database objects while recovery is in progress
+HINT:  Only RowExclusiveLock or less can be acquired on database objects during recovery.
 TRUNCATE reference_table;
-ERROR:  cannot execute TRUNCATE TABLE in a read-only transaction
+ERROR:  cannot acquire lock mode AccessExclusiveLock on database objects while recovery is in progress
+HINT:  Only RowExclusiveLock or less can be acquired on database objects during recovery.
 TRUNCATE citus_local_table;
-ERROR:  cannot execute TRUNCATE TABLE in a read-only transaction
+ERROR:  cannot acquire lock mode AccessExclusiveLock on database objects while recovery is in progress
+HINT:  Only RowExclusiveLock or less can be acquired on database objects during recovery.
 ALTER TABLE the_table ADD COLUMN c int;
 ERROR:  cannot acquire lock mode AccessExclusiveLock on database objects while recovery is in progress
 HINT:  Only RowExclusiveLock or less can be acquired on database objects during recovery.

src/test/regress/multi_follower_schedule

@@ -1,4 +1,3 @@
-test: turn_mx_off
 test: multi_follower_sanity_check
 test: follower_single_node
 test: multi_follower_select_statements
@@ -7,3 +6,4 @@ test: multi_follower_configure_followers
 
 # test that no tests leaked intermediate results. This should always be last
 test: ensure_no_intermediate_data_leak
+test: check_mx