ISPN-4807 NPE under high load when using async metadata writes for the Lucene Directory
ISPN-4807 Improve PerformanceCompareStressTest to better model the scenarious we're mostly interested in

Marked as ISPN-4807 as the new configuration of the test serves as stress-test to identify the NPE
ISPN-4544 BaseWordCountMapReduceTest#testCombinerForDistributedReductionWithException doesn't actually test reduce exception