Directly store the transition target on LookupResult in TransitionResult.

test/mjsunit/regress/regress-lookup-transition.js

Index: test/mjsunit/regress/regress-lookup-transition.js
diff --git a/test/mjsunit/regress/regress-lookup-transition.js b/test/mjsunit/regress/regress-lookup-transition.js
new file mode 100644
index 0000000000000000000000000000000000000000..9b329393062bbc6c71cf0ce83cfb6cdbb8196a4d
--- /dev/null
+++ b/test/mjsunit/regress/regress-lookup-transition.js
@@ -0,0 +1,14 @@
+// Copyright 2014 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: --harmony-proxies --expose-gc
+
+var proxy = Proxy.create({ getPropertyDescriptor:function(key) {
+  gc();
+}});
+
+function f() { this.x = 23; }
+f.prototype = proxy;
+new f();
+new f();