Fix tests that use a 0-length timeout.

test/runner/pause_after_load_test.dart

Index: test/runner/pause_after_load_test.dart
diff --git a/test/runner/pause_after_load_test.dart b/test/runner/pause_after_load_test.dart
index a67ea855fed7759109a56eeacd7835a705f76dee..91969ba4b6c86717407ef9ce05bb0f14b39613d7 100644
--- a/test/runner/pause_after_load_test.dart
+++ b/test/runner/pause_after_load_test.dart
@@ -241,12 +241,16 @@ void main() {
 
   test("disables timeouts", () {
     d.file("test.dart", """
+import 'dart:async';
+
 import 'package:test/test.dart';
 
 void main() {
   print('loaded test 1!');
 
-  test("success", () {}, timeout: new Timeout(Duration.ZERO));
+  test("success", () async {
+    await new Future.delayed(Duration.ZERO);
+  }, timeout: new Timeout(Duration.ZERO));
 }
 """).create();