Bug 395738 - Bad row mapping when join fetching an abstract entity with column discriminator.
             Fix by J LM<jlamande@gmail.com>
             Standalone jUnit test provided by J LM<jlamande@gmail.com> integrated into JPA tests.

Signed-off-by: Tomas Kraus <tomas.kraus@oracle.com>
Reviewed-by: Lucas Jungmann <lucas.jungmann@oracle.com>