QPID-5038: [Java Broker Tests] Fix leak from message store tests

Ensure that all message store tests close the message store under test on all code paths. This prevents a BDB thread leak manifesting
when running a BDB profile.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1510189 13f79535-47bb-0310-9956-ffa450edef68