Build failures not being reported in an easily digested form.

Context

In https://buildstream.gitlab.io/-/benchmarks/-/jobs/153038035/artifacts/results_cache/results-2019-01-29-00:01:55.json A failure is reported in tests associated with buildstream commit "a3e2cdd207fc610f9310bce122045f05734ccae2", unfortunately the error is only reported in logging and not displayed or rendered in any form apart from the result being omitted in generated graphs and HTML.

It would be preferable for some sort of error reporting showing failure to be present in both the gitlab runner and gitlab.io instance (for easy feedback).

Task Description

• Add error file outputting to benchmark running / result processing.
• Add web and html pages to detail failures as part of the results bundle.
• Investigate/add some sort of feedback in the gitlab runner to provide some sort of immediate information on failures.

Acceptance Criteria

Error reporting should be provided as part of the gitlab.io html rendering (a web page titled "ERRORS" or such like. If possible some sort of reasonable feedback should be provided in the runner.