More explicit reference to RISCOF would be helpful in the docs

[lev-rumyantsev]

I was trying to find a way to build these tests but couldn't find any instructions. Only after searching the internet I found references that it's build and run using RISCOF. Currently it's mentioned as For more details on the usage of the current framework see : [RISCOF](https://riscof.readthedocs.io/), which sounds like an optional step: if you don't need details you can skip it. But apparently it's the core engine of everything.

So I'd rephase to something along the lines of Refer to [RISCOF](https://riscof.readthedocs.io/) for instrucitons on how to build these tests