Make tests pass on 1-core VMs

[bmwiedemann]

found while working on reproducible builds for openSUSE

To reproduce there
osc checkout openSUSE:Factory/benchmark && cd $_
osc build -j1 --vm-type=kvm

[coveralls]

Coverage remained the same at 86.877% when pulling 7c917eb on bmwiedemann:j1 into af441fc on google:master.

[AppVeyorBot]

✅ Build benchmark 1374 completed (commit 162e569dae by @bmwiedemann)

[LebedevRI]

Looks ok, but do we want to actually check that we print s only when there is just one cpu?

[bmwiedemann]

I don't care. I could even live with a program telling me that I have "1 CPUs". Keeping code simple is always a plus for future maintainability.

[LebedevRI]

Ok, LG to me. I, too, don't think that s matters much.
If no one else has an opinion i'll merge next week.

[dmah42]

LGTM