Array() in optimized code can create with wrong ElementsKind in corner cases.

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 10388 matching lines @@
 
   static bool HasReadOnlyLength(Handle<JSArray> array);
   static bool WouldChangeReadOnlyLength(Handle<JSArray> array, uint32_t index);
   static MaybeHandle<Object> ReadOnlyLengthError(Handle<JSArray> array);
 
   // Initialize the array with the given capacity. The function may
   // fail due to out-of-memory situations, but only if the requested
   // capacity is non-zero.
   static void Initialize(Handle<JSArray> array, int capacity, int length = 0);
 
+  // If the JSArray has fast elements, and new_length would result in
+  // normalization, returns true.
+  static inline bool SetElementsLengthWouldNormalize(
+      Heap* heap, Handle<Object> new_length_handle);
+
   // Initializes the array to a certain length.
   inline bool AllowsSetElementsLength();
   // Can cause GC.
   MUST_USE_RESULT static MaybeHandle<Object> SetElementsLength(
       Handle<JSArray> array,
       Handle<Object> length);
 
   // Set the content of the array to the content of storage.
   static inline void SetContent(Handle<JSArray> array,
                                 Handle<FixedArrayBase> storage);
@@ skipping 656 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_