Add in-progress message for long running tests

[lefou]

The idea is, that for long running tests (integration tests), it would be good to have some indicator what test is currently running. I don't know what a good timeout could be, 5 - 10 seconds come to mind.

The output could something like:

* SUCCESS A short and quick test
... next test starts but no output for some time. After e.g. 10 seconds we see
* RUNNING A complex test
... even more time passes without output
* SUCCESS A complex test