Port HBASE-3380 (Master failover can split logs of live servers) to 92/trunk (definitely bring in config params, decide if we need to do more to fix the bug)

Over in HBASE-3380 we were having some TestMasterFailover flakiness. We added some more config parameters to better control the master startup loop where it waits for RS to heartbeat in. We had thought at the time that 92 would have a different solution but it is still relying on heartbeats to learn about RSs.

For now, we should definitely bring these config params into 92/trunk. Otherwise this is an incompatible regression and adding these will also make things like what was just reported over in HBASE-4603 trivial to fix in an optimal way.