Abort tracing in type inference in the presence of await.

tests/compiler/dart2js_extra/22895.dart

Index: tests/compiler/dart2js_extra/22895.dart
diff --git a/runtime/observatory/lib/src/debugger/debugger.dart b/tests/compiler/dart2js_extra/22895.dart
similarity index 52%
copy from runtime/observatory/lib/src/debugger/debugger.dart
copy to tests/compiler/dart2js_extra/22895.dart
index 97a6ff5dadc04df3e0939b6574835d4f31f292f4..73f120db967ce2d4bb096032f263c2d82163cb4f 100644
--- a/runtime/observatory/lib/src/debugger/debugger.dart
+++ b/tests/compiler/dart2js_extra/22895.dart
@@ -2,11 +2,10 @@
 // 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.
 
-part of debugger;
+// Regression test for http://dartbug.com/22895/
+// Ensure that the type graph is retained in presence of await.
 
-// TODO(turnidge): Move more of ObservatoryDebugger to this class.
-abstract class Debugger {
-  Isolate get isolate;
-  ServiceMap get stack;
-  int get currentFrame;
+main() async {
+  var closures = [(x, y) => x + y];
+  print(((await closures)[0])(4, 2));
 }