fixes #616, statics on callable functions

tool/input_sdk/private/ddc_runtime/classes.dart

 // Copyright (c) 2015, 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.
 
 /// This library defines the operations that define and manipulate Dart
 /// classes.  Included in this are:
 ///   - Generics
 ///   - Class metadata
 ///   - Extension methods
 ///
@@ skipping 450 matching lines @@
 ///         function Foo { function call(...args) { ... } ... return call; },
 ///         class Foo { call(x) { ... } });
 ///     ...
 ///       let f = new lib.Foo();
 ///       f(42);
 callableClass(callableCtor, classExpr) {
   JS('', '#.prototype = #.prototype', callableCtor, classExpr);
   // We're not going to use the original class, so we can safely replace it to
   // point at this constructor for the runtime type information.
   JS('', '#.prototype.constructor = #', callableCtor, callableCtor);
-  JS('', '#.__proto__ = #.__proto__', callableCtor, classExpr);
+  JS('', '#.__proto__ = #', callableCtor, classExpr);
   return callableCtor;
 }
 
 /// Given a class and an initializer method name and a call method, creates a
 /// constructor function with the same name.
 ///
 /// For example it can be called with `new SomeClass.name(args)`.
 ///
 /// The constructor
 defineNamedConstructorCallable(clazz, name, ctor) => JS(
     '',
     '''(() => {
   ctor.prototype = $clazz.prototype;
   // Use defineProperty so we don't hit a property defined on Function,
   // like `caller` and `arguments`.
   $defineProperty($clazz, $name, { value: ctor, configurable: true });
 })()''');