Allow role created by new test to log in on Windows.

We must tell init about each role name we plan to connect as,
else SSPI auth fails.  Similar to previous patches such as
e3fbc9a8d.

Oversight in a39e53a70, per buildfarm member unicorn.

src/test/modules/test_autovacuum/t/001_parallel_autovacuum.pl

@@ -28,7 +28,8 @@ sub prepare_for_next_test
 }
 
 my $node = PostgreSQL::Test::Cluster->new('main');
-$node->init;
+
+$node->init('auth_extra' => [ '--create-role', 'regress_dbowner' ]);
 
 # Limit to one autovacuum worker and disable autovacuum logging globally
 # (enabled only on the test table) so that log checks below match only