Optimizations for the timed version of DAGClient.getStatus

From https://issues.apache.org/jira/browse/TEZ-1967?focusedCommentId=14325037&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14325037

• The sleep within the AM can be improved via monitors.
• INITED state is returned when communicating with the AM, SUBMITTED state is returned when communicating with the RM. That could be used to optimize the flow.