pkg/intl: updated for latest unittest deprecations

pkg/intl/test/find_default_locale_standalone_test.dart

Index: pkg/intl/test/find_default_locale_standalone_test.dart
diff --git a/pkg/intl/test/find_default_locale_standalone_test.dart b/pkg/intl/test/find_default_locale_standalone_test.dart
index f0df693608f5525cb096c66fef1774d63c7aa4cb..a89f8ad122b2b3787926ff87206314a61e22f1e4 100644
--- a/pkg/intl/test/find_default_locale_standalone_test.dart
+++ b/pkg/intl/test/find_default_locale_standalone_test.dart
@@ -15,7 +15,7 @@ main() {
     // and then verify that it's actually the correct value.
     // We have no way of getting this reliably for Windows, so it will fail.
     Intl.systemLocale = "xx_YY";
-    var callback = expectAsync1(verifyLocale);
+    var callback = expectAsync(verifyLocale);
     findSystemLocale().then(callback);
   });
 }