Revert of Only use FreeSpace objects in the free list.

src/allocation-tracker.cc

Index: src/allocation-tracker.cc
diff --git a/src/allocation-tracker.cc b/src/allocation-tracker.cc
index 1ad86b88ff8679a1dbf9568eaa8ee7fd022f331c..7534ffb82fd21f007befd70b52dd410dd455335d 100644
--- a/src/allocation-tracker.cc
+++ b/src/allocation-tracker.cc
@@ -227,7 +227,9 @@
 
   // Mark the new block as FreeSpace to make sure the heap is iterable
   // while we are capturing stack trace.
-  heap->CreateFillerObjectAt(addr, size);
+  FreeListNode::FromAddress(addr)->set_size(heap, size);
+  DCHECK_EQ(HeapObject::FromAddress(addr)->Size(), size);
+  DCHECK(FreeListNode::IsFreeListNode(HeapObject::FromAddress(addr)));
 
   Isolate* isolate = heap->isolate();
   int length = 0;