[runtime] Add MapUpdater class that manages all kinds of map updates.

src/value-serializer.cc

Index: src/value-serializer.cc
diff --git a/src/value-serializer.cc b/src/value-serializer.cc
index 0e3a6a6e1e04346a71f287364bf6408238f63d73..aa8e46bcb14c0b96842785249b9ec0cb9dbb57d9 100644
--- a/src/value-serializer.cc
+++ b/src/value-serializer.cc
@@ -1664,8 +1664,8 @@ Maybe<uint32_t> ValueDeserializer::ReadJSObjectProperties(
                    ->NowContains(value)) {
             Handle<FieldType> value_type =
                 value->OptimalType(isolate_, expected_representation);
-            Map::GeneralizeFieldType(target, descriptor,
-                                     expected_representation, value_type);
+            Map::GeneralizeField(target, descriptor, expected_representation,
+                                 value_type);
           }
           DCHECK(target->instance_descriptors()
                      ->GetFieldType(descriptor)