test: update test-run (memory and test duration)

Now test-run reports memory occupied by tests and their duration (see
[1] and [2]).

Aside of this, there is a tiny code health change around waiting for
`box.info.status` value: it should not affect a visible test-run
behaviour ([3]).

[1]: https://github.com/tarantool/test-run/issues/277
[2]: https://github.com/tarantool/test-run/issues/286
[3]: https://github.com/tarantool/test-run/issues/301