ISPN-4873 Statetransfer thread pool deadlock

* Update LargeClusterStressTest to create a large number of caches
* Make StateRequestCommand implement TopologyAffectedCommand
ISPN-4941 Re-enabling rebalancing should not start a rebalance for a cache
in degraded mode
ISPN-3938 AdvancedAsyncCacheLoader.process() concurrency issues

Simplify ExecutorAllCompletionService to track the tasks itself instead of
using an ExecutorCompletionService.