[Arguments] Introduce a new backing store for non-strict arguments objects.

src/heap.cc

 // Copyright 2010 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 1712 matching lines @@
     if (!maybe_obj->ToObject(&obj)) return false;
   }
   set_external_unsigned_int_array_map(Map::cast(obj));
 
   { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_FLOAT_ARRAY_TYPE,
                                          ExternalArray::kAlignedSize);
     if (!maybe_obj->ToObject(&obj)) return false;
   }
   set_external_float_array_map(Map::cast(obj));
 
+  { MaybeObject* maybe_obj =
+        AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
+  set_non_strict_arguments_elements_map(Map::cast(obj));
+
   { MaybeObject* maybe_obj = AllocateMap(CODE_TYPE, kVariableSizeSentinel);
     if (!maybe_obj->ToObject(&obj)) return false;
   }
   set_code_map(Map::cast(obj));
 
   { MaybeObject* maybe_obj = AllocateMap(JS_GLOBAL_PROPERTY_CELL_TYPE,
                                          JSGlobalPropertyCell::kSize);
     if (!maybe_obj->ToObject(&obj)) return false;
   }
   set_global_property_cell_map(Map::cast(obj));
@@ skipping 4034 matching lines @@
 }
 
 
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 } }  // namespace v8::internal