ClusteredStatefulCacheListener should be a singleton

Currently, each SFSB Container registers an instance of ClusteredStatefulCacheListener with the SFSB cache. This is inefficient if there are many containers, as each gets passivation/activation callbacks and has to filter for the ones it's interested in. The callbacks don't do anything container-specific, so it should be possible to use a quasi-singleton ClusteredStatefulCacheListener and eliminate the filtering.

Quasi-singleton, because it's possible to have multiple SFSB caches; need one listener per cache.