ISPN-4054 Scripts to analyze test failures and corresponding issues

* find_unstable_tests.py - list the tests with the @Test(groups =
  "unstable") annotation
* find_unstable_tests_jira.py - list the tests with an open issue in JIRA
* find_unstable_tests_teamcity.py - list the tests with failures in CI
* diff_test_lists.py - find differences in the three sets of tests, e.g.
  tests with failures in CI and with an issue in JIRA but not in the
  unstable group.
CacheMBeanTest.testManagerStopRemovesCacheMBean wasn't stopping its cache manager on failure
Move more random failing tests to the unstable group

* ISPN-3631 - o.i.persistence.support.AsyncStoreEvictionTest
* ISPN-3994 - o.i.rest.IntegrationTest
* ISPN-4023 - o.i.server.test.rest.RESTCertSecurityTest
* ISPN-4026 - o.i.server.test.configs.ExampleConfigsTest
* ISPN-4017 - o.i.client.hotrod.BaseBulkGetKeysTest
* ISPN-4057 - o.i.server.test.clusteredcache.ClusteredCacheConfigurationTest
* ISPN-4058 - o.i.test.integration.as.cdi.GreetingServiceIT
* ISPN-4029 - o.i.commons.util.concurrent.NotifyingFutureTest
Update JIRA references in unstable tests

Also add alwaysRun = true @Before and @After methods where required
* For @Before, it's needed for test methods in other groups (e.g. unstable)
* For @After, it's needed otherwise the method won't run if the test failed