[field type tracking] Fix handling of cleared WeakCells.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index a29f48de081ebdc405437e567206c91773cafad3..004a4bd6020224b3756b8d4c15575f67ccb22e14 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -3833,8 +3833,8 @@ MaybeHandle<Map> Map::TryUpdate(Handle<Map> old_map) {
       case DATA: {
         HeapType* new_type = new_descriptors->GetFieldType(i);
         // Cleared field types need special treatment. They represent lost
-        // knowledge, so we must first generalize the old_type to "Any".
-        if (!FieldTypeIsCleared(new_details.representation(), new_type)) {
+        // knowledge, so we must first generalize the new_type to "Any".
+        if (FieldTypeIsCleared(new_details.representation(), new_type)) {
           return MaybeHandle<Map>();
         }
         PropertyType old_property_type = old_details.type();