Cleanup FreeSpace: Remove getter for address of next pointer

src/heap/objects-visiting.h

Index: src/heap/objects-visiting.h
diff --git a/src/heap/objects-visiting.h b/src/heap/objects-visiting.h
index 6b0381b56ee52eecdbccba6ad021df60bd698530..e9cd16c0a33591f030fc8f4a1d72dacc09706d8d 100644
--- a/src/heap/objects-visiting.h
+++ b/src/heap/objects-visiting.h
@@ -340,7 +340,7 @@ class StaticNewSpaceVisitor : public StaticVisitorBase {
   }
 
   INLINE(static int VisitFreeSpace(Map* map, HeapObject* object)) {
-    return FreeSpace::cast(object)->Size();
+    return FreeSpace::cast(object)->size();
   }
 
   INLINE(static int VisitJSArrayBuffer(Map* map, HeapObject* object));