Rationalize entityoptimisticlocking tests

Per parent task, these are being moved into the cluster section of the AS testsuite, as they use a persistence.xml that specifies use of JBoss Cache based second level caching.

But, none of the entities are actually configured for caching, so I don't see what the point of specifying JBC is.

Task: figure out whether the caching is actually relevant to the goal of these tests; if yes, actually enable it; if no, get rid of the second level cache configuration and move out of the cluster package.