Python test suite: add timestamp or elapsed time for tests

When jenkins times out during the test suite, there's no good way to tell how to fix it. In particular , is any test running longer than usual? What tests are running long? A time stamp, or elapsed time, or some variation (e.g. "report elapsed time if > 1 second") would be helpful. TBD whether it's better to do this per scenario item or whether it is even possible to group related tests (sum scenarios together).