HBASE-8934 Fix bunch of flaky tests

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1502627 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8934 Fix bunch of flaky tests ADDENDUM patch that fixes imports

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1502648 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd