Fix IdleNotification to correctly free objects.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 0cbe13f92fb26cdb730318ae56cde11cac517d23..6ff0de6bf31f75a533b397ef32713e0ecba0a045 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -4546,7 +4546,7 @@ bool Heap::IdleNotification() {
     last_idle_notification_gc_count_ = gc_count_;
 
   } else if (number_idle_notifications_ == kIdlesBeforeMarkCompact) {
-    CollectAllGarbage(kNoGCFlags);
+    CollectAllGarbage(kMakeHeapIterableMask);
     new_space_.Shrink();
     last_idle_notification_gc_count_ = gc_count_;
     number_idle_notifications_ = 0;