The locking tests are part of the core JPA functionality. I don't see them as part of our integration with another product (ie a Bean Validation provider, or the TCK). If we split out other long running tests it might make sense to create an openjpa-tests module but integration didn't seem right to me.
There's really no good place to put these tests. Conceptually they belong in openjpa-persistence-jdbc, but we don't have fine grained control of the JVM used to run the tests (and the derby settings are per jvm).