HBASE-11029 Increase wait in TestSplitTransactionOnCluster.split.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1588530 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10988; Addendum: increase wait to 20s.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1588541 13f79535-47bb-0310-9956-ffa450edef68