Wait for subscription to sync in t/031_column_list.sql

One of the TAP tests added in 923def9a53 did not wait after creating a
subscription, and wait_for_catchup is not sufficient for this. So if the
tablesync workers happen do not complete quickly enough, the test won't
see the expected results.

This probably explains intermittent failures on a couple buildfarm
animals (komodoensis, petalura and snapper).

Reported-by: Tom Lane
Discussion: https://postgr.es/m/170549.1648330634@sss.pgh.pa.us

src/test/subscription/t/031_column_list.pl

@@ -722,7 +722,7 @@ $node_subscriber->safe_psql('postgres', qq(
 	CREATE SUBSCRIPTION sub1 CONNECTION '$publisher_connstr' PUBLICATION pub8;
 ));
 
-$node_publisher->wait_for_catchup('sub1');
+wait_for_subscription_sync($node_subscriber);
 
 $node_publisher->safe_psql('postgres', qq(
 	INSERT INTO test_part_c VALUES (3, 7, 8);