Fix new TAP test for 2PC transactions and PITRs on Windows

The test added by 595b9cba forgot that on Windows it is necessary to set
up pg_hba.conf (see PostgresNode::set_replication_conf) with a specific
entry or base backups fail.  Any node that requires to support
replication just needs to pass down allows_streaming at initialization.
This updates the test to do so.  Simplify things a bit while on it.

Per buildfarm member fairywren.  Any Windows hosts running this test
would have failed, and I have reproduced the problem as well.

Backpatch-through: 10

src/test/recovery/t/023_pitr_prepared_xact.pl

@@ -8,11 +8,9 @@ use File::Compare;
 
 # Initialize and start primary node with WAL archiving
 my $node_primary = get_new_node('primary');
-$node_primary->init(has_archiving => 1);
+$node_primary->init(has_archiving => 1, allows_streaming => 1);
 $node_primary->append_conf(
 	'postgresql.conf', qq{
-max_wal_senders = 10
-wal_level = 'replica'
 max_prepared_transactions = 10});
 $node_primary->start;
 
@@ -30,7 +28,6 @@ $node_pitr->init_from_backup(
 	has_restoring => 1);
 $node_pitr->append_conf(
 	'postgresql.conf', qq{
-max_prepared_transactions = 10
 recovery_target_name = 'rp'
 recovery_target_action = 'promote'});