Remove deprecated ms arguments for Timer and Future.

tests/standalone/io/raw_secure_server_closing_test.dart

Index: tests/standalone/io/raw_secure_server_closing_test.dart
diff --git a/tests/standalone/io/raw_secure_server_closing_test.dart b/tests/standalone/io/raw_secure_server_closing_test.dart
index 1f8116d48806b34b0677156257b555ad556c5a2d..0fa81210843970d1fb790a5d4cbf9d94dac090a0 100644
--- a/tests/standalone/io/raw_secure_server_closing_test.dart
+++ b/tests/standalone/io/raw_secure_server_closing_test.dart
@@ -99,7 +99,7 @@ testPauseServerSocket() {
         connection.shutdown(SocketDirection.SEND);
       });
     }
-    new Timer(500, (_) {
+    new Timer(const Duration(milliseconds: 500), () {
       subscription.resume();
       resumed = true;
       for (int i = 0; i < socketCount; i++) {