Use OrderedHashTables as the backing store of JSSet and JSMap

src/heap.cc

 // 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 2892 matching lines @@
 
     for (unsigned i = 0; i < ARRAY_SIZE(struct_table); i++) {
       const StructTable& entry = struct_table[i];
       Map* map;
       if (!AllocateMap(entry.type, entry.size)->To(&map))
         return false;
       roots_[entry.index] = map;
     }
 
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, hash_table)
+    ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, ordered_hash_table)
 
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, function_context)
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, catch_context)
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, with_context)
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, block_context)
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, module_context)
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, global_context)
 
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, native_context)
     native_context_map()->set_dictionary_map(true);
@@ skipping 4942 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal