HBASE-9082 A bunch of tests have client retries only but bulid boxes are contended and overloaded

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1508489 13f79535-47bb-0310-9956-ffa450edef68
HBASE-9052 Prevent split/merged region from assigning again

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1508518 13f79535-47bb-0310-9956-ffa450edef68