Enhancements to the test platform

This removes the reflection used in the tests, that are ever so vital for the lifecycle of the tests.

I named the interfaces after the corresponding `Runner`s, so [HibernateTest](https://github.com/querydsl/querydsl/compare/junit?expand=1#diff-10) for [HibernateTestRunner](https://github.com/querydsl/querydsl/compare/junit?expand=1#diff-18) and [JPATest](https://github.com/querydsl/querydsl/compare/junit?expand=1#diff-8) for [JPATestRunner](https://github.com/querydsl/querydsl/compare/junit?expand=1#diff-19)

I did notice that some tests are in the `com.mysema.query` package, and some in `com.mysema.query.jpa`.