Reland "Only use FreeSpace objects in the free list"

src/heap/spaces-inl.h

Index: src/heap/spaces-inl.h
diff --git a/src/heap/spaces-inl.h b/src/heap/spaces-inl.h
index 9cb292e3df4adfdf53e3b716560df5399479cc43..cfa23255c41c10b09de336b5bce3198764bd1186 100644
--- a/src/heap/spaces-inl.h
+++ b/src/heap/spaces-inl.h
@@ -305,14 +305,6 @@ intptr_t LargeObjectSpace::Available() {
   return ObjectSizeFor(heap()->isolate()->memory_allocator()->Available());
 }
 
-
-bool FreeListNode::IsFreeListNode(HeapObject* object) {
-  Map* map = object->map();
-  Heap* heap = object->GetHeap();
-  return map == heap->raw_unchecked_free_space_map() ||
-         map == heap->raw_unchecked_one_pointer_filler_map() ||
-         map == heap->raw_unchecked_two_pointer_filler_map();
-}
 }
 }  // namespace v8::internal