Fix a few more timeout tests.

test/runner/browser/runner_test.dart

Index: test/runner/browser/runner_test.dart
diff --git a/test/runner/browser/runner_test.dart b/test/runner/browser/runner_test.dart
index dcd18c694b6fca0d1981c0a28517c88a3b9b7b60..07af765a414cd323db2482a5f6cfd999a6e76912 100644
--- a/test/runner/browser/runner_test.dart
+++ b/test/runner/browser/runner_test.dart
@@ -459,7 +459,7 @@ import 'dart:async';
 import 'package:test/test.dart';
 
 void main() {
-  test("timeout", () {});
+  test("timeout", () => new Future.delayed(Duration.ZERO));
 }
 ''').create();
 
@@ -511,8 +511,11 @@ import 'dart:async';
 import 'package:test/test.dart';
 
 void main() {
-  test("fail", () => throw 'oh no', onPlatform: {
-    "browser": new Timeout(new Duration(seconds: 0))
+  test("fail", () async {
+    await new Future.delayed(Duration.ZERO);
+    throw 'oh no';
+  }, onPlatform: {
+    "browser": new Timeout(Duration.ZERO)
   });
 }
 ''').create();
@@ -618,7 +621,10 @@ import 'dart:async';
 import 'package:test/test.dart';
 
 void main() {
-  test("fail", () => throw 'oh no');
+  test("fail", () async {
+    await new Future.delayed(Duration.ZERO);
+    throw 'oh no';
+  });
 }
 ''').create();