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
14793f471, 973542866.

Oversight in 208927e65, per buildfarm member drongo.
(Although that was back-patched to v13, the test script
only exists in v16 and up.)

contrib/pg_prewarm/t/001_basic.pl

@@ -11,7 +11,7 @@ use Test::More;
 
 my $node = PostgreSQL::Test::Cluster->new('main');
 
-$node->init;
+$node->init('auth_extra' => [ '--create-role', 'test_user' ]);
 $node->append_conf(
 	'postgresql.conf',
 	qq{shared_preload_libraries = 'pg_prewarm'