ISPN-4520 JdbcBinaryStoreTest.testLoadAndStoreWithLifespanAndIdle random failures

* Increased the timeout to avoid false positives
ISPN-4478 ServerFailureRetrySingleOwnerTest should remove listener

* Before, the error inducing listener was not being removed, and that
was not appearing as a result that each test was creating a new bunch
of cache managers. Now, clean up is done after the test class has
finished and the listeners are correctly removed.
ISPN-4499 Prevent shadowing user-defined jgroups configuration file
ISPN-1951 Use MERGE3 in the default UDP configuration

TEST_PING needed some changes, as MERGE3 doesn't trigger Discovery.findMembers()
Smaller timer pool and queue.
Still causes lots of failures.