[builtins] Fix Array.prototype.concat bug

src/elements.h

 // Copyright 2012 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_ELEMENTS_H_
 #define V8_ELEMENTS_H_
 
 #include "src/elements-kind.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
@@ skipping 37 matching lines @@
                           PropertyFilter filter = ALL_PROPERTIES) = 0;
 
   inline bool HasElement(Handle<JSObject> holder, uint32_t index,
                          PropertyFilter filter = ALL_PROPERTIES) {
     return HasElement(holder, index, handle(holder->elements()), filter);
   }
 
   virtual Handle<Object> Get(Handle<JSObject> holder, uint32_t entry) = 0;
 
   virtual PropertyDetails GetDetails(JSObject* holder, uint32_t entry) = 0;
+  virtual bool HasAccessors(JSObject* holder) = 0;
 
   // Modifies the length data property as specified for JSArrays and resizes the
   // underlying backing store accordingly. The method honors the semantics of
   // changing array sizes as defined in EcmaScript 5.1 15.4.5.2, i.e. array that
   // have non-deletable elements can only be shrunk to the size of highest
   // element that is non-deletable.
   virtual void SetLength(Handle<JSArray> holder, uint32_t new_length) = 0;
 
   // Deletes an element in an object.
   virtual void Delete(Handle<JSObject> holder, uint32_t entry) = 0;
@@ skipping 117 matching lines @@
                      bool allow_appending = false);
 
 MUST_USE_RESULT MaybeHandle<Object> ArrayConstructInitializeElements(
     Handle<JSArray> array,
     Arguments* args);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ELEMENTS_H_