Use distinct maps for oddballs with special handling in the type system.

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5581 matching lines @@
   static const int kStringEncodingMask = 0x4;
   static const int kExternalTwoByteRepresentationTag = 0x02;
   static const int kExternalAsciiRepresentationTag = 0x06;
 
   static const int kIsolateEmbedderDataOffset = 0 * kApiPointerSize;
   static const int kIsolateRootsOffset = 5 * kApiPointerSize;
   static const int kUndefinedValueRootIndex = 5;
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
   static const int kFalseValueRootIndex = 9;
-  static const int kEmptyStringRootIndex = 152;
+  static const int kEmptyStringRootIndex = 159;
 
   static const int kNodeClassIdOffset = 1 * kApiPointerSize;
   static const int kNodeFlagsOffset = 1 * kApiPointerSize + 3;
   static const int kNodeStateMask = 0xf;
   static const int kNodeStateIsWeakValue = 2;
   static const int kNodeStateIsPendingValue = 3;
   static const int kNodeStateIsNearDeathValue = 4;
   static const int kNodeIsIndependentShift = 4;
   static const int kNodeIsPartiallyDependentShift = 5;
 
@@ skipping 1071 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_