CDAP-640 - Metrics Increase RunId max Entries 

This PR is to increase the for max entries for runId in Metrics Entity Table from (2^16) to (2^32) 

While testing this, we figured an issues with our levelDB getRow implementation, where the limit was ignored and due to that we were scanning the entire table for a simple incrementAndGet. This PR contains the fix for that as well.

Edit: See @abaranau comment. This PR has been changed, to recycle and use the old runId once we reach the 65k limit, than increase the runID range to 2^32.
https://issues.cask.co/browse/CDAP-640
can we do simple+i, metric+i too? Only if it doesn't make test very slow;)