[heap] MinorMC: Only iterate new space global handles for ptr updates

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index 673f1547b99f0e6325f2d86672a8a1edd349de26..99ad09b8a38c725fa65d47c0061388e3b061dfed 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -130,6 +130,8 @@ class GlobalHandles {
   // Iterates over all handles.
   void IterateAllRoots(RootVisitor* v);
 
+  void IterateAllNewSpaceRoots(RootVisitor* v);
+
   // Iterates over all handles that have embedder-assigned class ID.
   void IterateAllRootsWithClassIds(v8::PersistentHandleVisitor* v);