Correctly hook up materialized receiver into the evaluation context chain.

test/mjsunit/regress/regress-crbug-491943.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-debug-as debug
 
 var Debug = debug.Debug;
 var receiver = null;
 
 Debug.setListener(function(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;
   receiver = exec_state.frame(0).evaluate('this').value();
 });
 
-function f() { debugger; }
+
+function f() {
+  var context_local = 1;
+  (function() { return context_local; })();
+  debugger;
+}
 
 var expected = {};
 f.call(expected);
 
 assertEquals(expected, receiver);