Hibernate Envers GeneratedColumnTest fails on all databases

looks like we overlooked this change when backporting HHH-10889: https://github.com/hibernate/hibernate-orm/commit/f59dfa2522cbfbf818539aa1f308c565f26b017b#diff-edde32c26b58eaec5473869be5ef8bfd

it is a one-line change in org/hibernate/envers/test/integration/generated/SimpleEntity.java, we need to backport this into 5.1

The description of HHH-10889 says it is an issue only on Oracle, but I see the same with all databases. Tried backporting it on my machine and the issue was fixed.