HBASE-9107 [0.94] Backport HBASE-6950 TestAcidGuarantees system test now flushes too aggressively to 0.94

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1509533 13f79535-47bb-0310-9956-ffa450edef68