[runtime] Mark maps created as a result of field representation generalization as transition targets

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 1ffd3b5faca8947b63bda51462f4d2f371a72b81..fa2dcdbfc4fc6b15a97c48e9964bf10a003176b0 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9159,8 +9159,10 @@ Handle<Map> UpdateDescriptorForValue(Handle<Map> map, int descriptor,
   Handle<FieldType> type = value->OptimalType(isolate, representation);
 
   MapUpdater mu(isolate, map);
-  return mu.ReconfigureToDataField(descriptor, attributes, representation,
-                                   type);
+  Handle<Map> new_map =
+      mu.ReconfigureToDataField(descriptor, attributes, representation, type);
+  new_map->set_migration_target(true);
+  return new_map;
 }
 
 }  // namespace