[runtime] Stop cloning AccessorInfo, just rely on PropertyAttributes for readonly.

src/objects.h

 // Copyright 2015 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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 10178 matching lines @@
   DECL_ACCESSORS(name, Object)
   DECL_INT_ACCESSORS(flag)
   DECL_ACCESSORS(expected_receiver_type, Object)
   DECL_ACCESSORS(getter, Object)
   DECL_ACCESSORS(setter, Object)
   DECL_ACCESSORS(data, Object)
 
   // Dispatched behavior.
   DECLARE_PRINTER(AccessorInfo)
 
-  static void ClearSetter(Handle<AccessorInfo> info);
-
   inline bool all_can_read();
   inline void set_all_can_read(bool value);
 
   inline bool all_can_write();
   inline void set_all_can_write(bool value);
 
   inline bool is_special_data_property();
   inline void set_is_special_data_property(bool value);
 
   inline PropertyAttributes property_attributes();
@@ skipping 512 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_