Fixes async for two other language_2 tests.

Change-Id: Id805a913275468f70cfbe03e37f2534fad6aaab8
Reviewed-on: https://dart-review.googlesource.com/26221
Reviewed-by: Bob Nystrom <rnystrom@google.com>

tests/language_2/async_await_foreign_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 import 'package:expect/expect.dart';
+import 'package:async_helper/async_helper.dart';
 
 typedef Future<Null> Task();
 
@@ -65,8 +66,12 @@ Future<String> world() async {
   return 'world';
 }
 
-Future main() async {
-  var r2 = await world();
-  Expect.equals('hello', r1);
-  Expect.equals('world', r2);
+void main() {
+  asyncStart();
+  () async {
+    var r2 = await world();
+    Expect.equals('hello', r1);
+    Expect.equals('world', r2);
+    asyncEnd();
+  }();
 }

tests/language_2/async_call_test.dart

@@ -4,6 +4,7 @@
 
 import "dart:async";
 import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
 
 var result = "";
 
@@ -15,14 +16,18 @@ bar() async {
   result += "bar";
 }
 
-main() async {
-  var f = new Future(foo);
-  var b = bar();
-  Expect.equals("", result);
-  scheduleMicrotask(() => result += "micro");
-  await b;
-  await f;
+main() {
+  asyncStart();
+  () async {
+    var f = new Future(foo);
+    var b = bar();
+    Expect.equals("", result);
+    scheduleMicrotask(() => result += "micro");
+    await b;
+    await f;
 
-  // Validates that bar is scheduled as a microtask, before foo.
-  Expect.equals("barmicrofoo", result);
+    // Validates that bar is scheduled as a microtask, before foo.
+    Expect.equals("barmicrofoo", result);
+    asyncEnd();
+  }();
 }