Move Maps' back pointers from "transitions" to "constructor" field

src/objects-printer.cc

 // Copyright 2012 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.
 
 #include "src/v8.h"
 
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/heap/objects-visiting.h"
 #include "src/jsregexp.h"
@@ skipping 418 matching lines @@
   os << "\n - instance descriptors " << (owns_descriptors() ? "(own) " : "")
      << "#" << NumberOfOwnDescriptors() << ": "
      << Brief(instance_descriptors());
   if (FLAG_unbox_double_fields) {
     os << "\n - layout descriptor: " << Brief(layout_descriptor());
   }
   if (HasTransitionArray()) {
     os << "\n - transitions: " << Brief(transitions());
   }
   os << "\n - prototype: " << Brief(prototype());
-  os << "\n - constructor: " << Brief(constructor());
+  os << "\n - constructor: " << Brief(GetConstructor());
   os << "\n - code cache: " << Brief(code_cache());
   os << "\n - dependent code: " << Brief(dependent_code());
   os << "\n";
 }
 
 
 void CodeCache::CodeCachePrint(std::ostream& os) {  // NOLINT
   HeapObject::PrintHeader(os, "CodeCache");
   os << "\n - default_cache: " << Brief(default_cache());
   os << "\n - normal_type_cache: " << Brief(normal_type_cache());
@@ skipping 735 matching lines @@
   }
 }
 
 
 void JSObject::PrintTransitions(std::ostream& os) {  // NOLINT
   if (!map()->HasTransitionArray()) return;
   map()->transitions()->PrintTransitions(os, false);
 }
 #endif  // defined(DEBUG) || defined(OBJECT_PRINT)
 } }  // namespace v8::internal