Ensure that descriptors have a prototype.

tests/compiler/dart2js_extra/22776.dart

Index: tests/compiler/dart2js_extra/22776.dart
diff --git a/tests/language/regress_22579_test.dart b/tests/compiler/dart2js_extra/22776.dart
similarity index 55%
copy from tests/language/regress_22579_test.dart
copy to tests/compiler/dart2js_extra/22776.dart
index 76c8f42463fe87b21372d1f2da3a768cf0482fb6..c5af71756a442e6ce9329e2db4a27c0b23b525a9 100644
--- a/tests/language/regress_22579_test.dart
+++ b/tests/compiler/dart2js_extra/22776.dart
@@ -2,24 +2,21 @@
 // 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.
 
-import "dart:async";
-import "package:expect/expect.dart";
+// Regression test for http://dartbug.com/22776/
 
-foo() async {
-  try {
-    await 1;
-  } catch(e) {
-  }
-  throw "error";
-}
+import "package:expect/expect.dart";
+class A {}
 
-main() async {
-  var error = "no error";
+main() {
   try {
-    await foo();
+    print(id(new Duration(milliseconds: 10)));
+    print(id(3) ~/ new A());
   } catch (e) {
-    error = e;
+    print("Error '$e' ${e.runtimeType}");
   }
-  Expect.equals("error", error);
 }
 
+@AssumeDynamic()
+@NoInline()
+id(x) => x;
+