Resolve "Errors in tests not reporting as build failures"

Description

When benchmarking testing approach fails (as opposed to a benchmark test failing) and no results are generated the gitlab pipeline continues without stopping. The pipeline should stop at the 1st failure

Changes proposed in this merge request:

• Add checks in the ci run script to make sure that results files are generated.

This merge request, when merged, will address issue/bug:

https://gitlab.com/BuildStream/benchmarks/issues/16

Closes #16 (closed)