Revert of [strong] Object literals create strong objects

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 103a3086651552a101ddc678c0537cc48622592e..fca1e1c1ca8abc821566f8e697fd591c7705e098 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -2386,18 +2386,14 @@
 
 Handle<Map> Factory::ObjectLiteralMapFromCache(Handle<Context> context,
                                                int number_of_properties,
-                                               bool is_strong,
                                                bool* is_result_from_cache) {
   const int kMapCacheSize = 128;
 
   // We do not cache maps for too many properties or when running builtin code.
-  // TODO(rossberg): cache strong maps properly
-  if (number_of_properties > kMapCacheSize || is_strong ||
+  if (number_of_properties > kMapCacheSize ||
       isolate()->bootstrapper()->IsActive()) {
     *is_result_from_cache = false;
-    Handle<Map> map = Map::Create(isolate(), number_of_properties);
-    if (is_strong) map->set_is_strong(true);
-    return map;
+    return Map::Create(isolate(), number_of_properties);
   }
   *is_result_from_cache = true;
   if (number_of_properties == 0) {