Enhancer dirty tracking doesn't work with inherited entities

Given these two classes:

Then this code:

One would expect the "title" and "oca" fields to be dirty. However, Hibernate says only the "oca" field is dirty.

It appears the enhancer's dirty checker doesn't correctly handle inherited fields.

Here's a pull request which includes a test case demonstrating the issue: https://github.com/hibernate/hibernate-orm/pull/1654