ISPN-3375 Map/Reduce jobs with small value sizes fail because of timeouts
putting intermediate keys into the cache

When the number of intermediate values per key is large, split list the
values in chunks based on stateTransfer.chunkSize.
ISPN-3375 Improve default JGroups configuration

* Make TP.max_bundle_size and FRAG2.frag_size the same, 30k
  (As datagrams larger than 32k are not always supported.)
* Enable the INTERNAL thread pool
* Increase the UFC/MFC.max_credits
* Configure FD_ALL.interval so that a node is suspected only after 5 missed
  heartbeats