[deoptimizer] Support materialization of ContextExtension.

test/mjsunit/regress/regress-crbug-644245.js

 // Copyright 2016 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: --allow-natives-syntax
+// Flags: --allow-natives-syntax --turbo --turbo-escape
 
-Array.prototype.__proto__ = null;
-var prototype = Array.prototype;
 function f() {
-  prototype.lastIndexOf({});
+  try {
+    throw "boom";
+  } catch(e) {
+    %_DeoptimizeNow();
+  }
 }
+
 f();
 f();
 %OptimizeFunctionOnNextCall(f);
 f();