HST integration tests can hang

In HSTTWO-3795, the resource lifecycle management was moved to the HstDelegateeFilterBean. Lifecycle management for example takes care that jcr session which are borrowed from the session pool are returned to the pool.

However, some integration tests invoke an HST pipeline, borrowing sessions from the pool, but never invoke HstDelegateeFilterBean, and therefor never return the sessions to the pool. When a test does a lot of pipeline invocations, the session pools get exhausted, halting the tests