Add test of OpenSCALING benchmark models for large-scale systems

[casella]

https://gitlab.liu.se/openscaling/work-products/d3.2-open-source-benchmark-models-for_lss is a public deliverable of the OpenSCALING project.

We should add it to the library testsuite, I'd say twice, once with default settings and once with --newBackend to see what performance we can get with the NB.