Enable await in for and for-in loops.

tests/language/await_future_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // VMOptions=--enable_async --optimization-counter-threshold=5
 
 import 'package:expect/expect.dart';
 
 import 'dart:async';
 
@@ skipping 140 matching lines @@
   };
   var k = 0;
   do {
     do {
       k++;
     } while (0 < (await decI()));
   } while((await decJ()) > 0);
   return k;
 }
 
+awaitFor() async {
+  var asyncInc = (p) async => p+1;
+  var k = 0;
+  for (int j = (await bar(0)), i = (await bar(1));
+       j < (await bar(5));
+       j = (await asyncInc(j)), i = (await asyncInc(i))) {
+    k += i;
+    k += j;
+  }
+  return k;
+}
+
+awaitForIn() async {
+  var list = ['a', 'b', 'c'];
+  var k = '';
+  for (var c in (await bar(list))) {
+    k += c;
+  }
+  return k;
+}
+
 main() async {
   var result;
   for (int i = 0; i < 10; i++) {
     result = await foo();
     Expect.equals(30, result);
     result = await quaz(17);
     Expect.equals(17, result);
     result = await quazz();
     Expect.equals(2, result);
     result = await nesting();
@@ skipping 17 matching lines @@
     result = await awaitElseIf(4);
     Expect.equals("p<5", result);
     result = await awaitElseIf(5);
     Expect.equals("p==5", result);
     result = await awaitNestedWhile(5,3);
     Expect.equals(15, result);
     result = await awaitNestedWhile(4,6);
     Expect.equals(24, result);
     result = await awaitAsUnary(bar(1), bar(2));
     Expect.equals(3, result);
+    result = await awaitFor();
+    Expect.equals(25, result);
+    result = await awaitForIn();
+    Expect.equals('abc', result);
   }
 }