Heap profiler: skip byte arrays that represent free list blocks when counting allocated objects.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 76b88ef7f0c1423ef9896a7e602812879ed3d79d..a51a667b315ad2f1e274782906768bcd0f179317 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -1423,6 +1423,8 @@ class FreeListNode: public HeapObject {
     return reinterpret_cast<FreeListNode*>(HeapObject::FromAddress(address));
   }
 
+  static inline bool IsFreeListNode(HeapObject* object);
+
   // Set the size in bytes, which can be read with HeapObject::Size().  This
   // function also writes a map to the first word of the block so that it
   // looks like a heap object to the garbage collector and heap iteration