rtc_time: test agent timeouts

Break the test up into four, keeping each well below the 60 second
timeout for the test agents. Overhead for the splitting up is an
additional 10 seconds in order to complete all four of the tests
instead of one. typical single test completion is 22.5 seconds.

Change-Id: If8e9a6c7dfd505a9fbc73e9248be4eb2b61521e5
1 file changed