JPA (Hibernate) second level cache (additional) testing requirements

This jira is a placeholder for collecting requirements for (additional) JPA second level cache testing. I asked rhn-support-sfikes for his input here, as he has helped many customers with various 2lc issues.

Others are welcome to add ideas here as well, as to what additional 2lc testing we should do in the WF or external QE testsuite.

Current 2lc tests in WildFly (external QE testsuite has zero 2lc tests):

1. Clustered test https://github.com/wildfly/wildfly/blob/master/testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/jpa2lc/ClusteredJPA2LCTestCase.java
2. Clustered extended persistence context failover test https://github.com/wildfly/wildfly/blob/master/testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/ejb/xpc/StatefulWithXPCFailoverTestCase.java
3. non-JPA testing https://github.com/wildfly/wildfly/tree/master/testsuite/integration/basic/src/test/java/org/jboss/as/test/integration/hibernate
4. JPA testing https://github.com/wildfly/wildfly/tree/master/testsuite/integration/basic/src/test/java/org/jboss/as/test/integration/jpa/secondlevelcache