Make 009_twophase.pl test pass with recovery_min_apply_delay set

The test failed if you ran the regression tests with TEMP_CONFIG with
recovery_min_apply_delay = '500ms'. Fix the race condition by waiting
for transaction to be applied in the replica, like in a few other
tests.

The failing test was introduced in commit cbfbda7. Backpatch to all
supported versions like that commit (except v12, which is no longer
supported).

Reported-by: Alexander Lakhin
Discussion: https://www.postgresql.org/message-id/09e2a70a-a6c2-4b5c-aeae-040a7449c9f2@gmail.com

Author: hlinnaka

src/test/recovery/t/009_twophase.pl

@@ -319,6 +319,7 @@ sub configure_and_reload
 
 $cur_primary->psql(
 	'postgres', "
+	SET synchronous_commit='remote_apply'; -- To ensure the standby is caught up
 	CREATE TABLE t_009_tbl_standby_mvcc (id int, msg text);
 	BEGIN;
 	INSERT INTO t_009_tbl_standby_mvcc VALUES (1, 'issued to ${cur_primary_name}');