ISPN-4544 testCombinerForDistributedReduction issue

Master only. Will should review. See https://issues.jboss.org/browse/ISPN-4544 for more details
I wonder if having it more like what you had before would be better where you checked the exception in the test.  I think verifying the nested exception is present might be best.  Unfortunately I don't trust expectedException for CacheException when we wrap everything in it :(