Fix deserializer to understand direct pointers from code to cell payloads.

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 12224)
+++ src/objects.h	(working copy)
@@ -7915,6 +7915,14 @@
   // Casting.
   static inline JSGlobalPropertyCell* cast(Object* obj);
 
+  static inline JSGlobalPropertyCell* FromValueAddress(Address value) {
+    return cast(FromAddress(value - kValueOffset));
+  }
+
+  inline Address ValueAddress() {
+    return address() + kValueOffset;
+  }
+
 #ifdef DEBUG
   void JSGlobalPropertyCellVerify();
 #endif