Remove deprecated ms arguments for Timer and Future.

tests/standalone/io/secure_server_closing_test.dart

Index: tests/standalone/io/secure_server_closing_test.dart
diff --git a/tests/standalone/io/secure_server_closing_test.dart b/tests/standalone/io/secure_server_closing_test.dart
index 794c54f32f179ba9f37e54965f0ad1757819e0ab..fde898c35994349522c4439f0be4f615fff0d673 100644
--- a/tests/standalone/io/secure_server_closing_test.dart
+++ b/tests/standalone/io/secure_server_closing_test.dart
@@ -105,7 +105,7 @@ testPauseServerSocket() {
         connection.close();
       });
     }
-    new Timer(500, (_) {
+    new Timer(const Duration(milliseconds: 500), () {
       subscription.resume();
       resumed = true;
       for (int i = 0; i < socketCount; i++) {