Make it possible to use marker_uilints with cargo-nextest

[Veetaha]

cargo-nextest is an awesome tool that considerably increases the tests performance. I won't describe all the problems that it solves and how it does that. This can be found in their home page.

The problem is that marker_uilints doesn't support cargo-nextest right now. To be compatible with it this crate must implement the subset of libtest CLI API that cargo-nextest requires.

[xFrednet]

Clippy has some boilerplate to also support cargo-nextest:

https://github.com/rust-lang/rust-clippy/blob/7408f1d231a5e223a2ab01032ffd1778bcb6e0f1/tests/compile-test.rs#L326

I haven't used it yet, but this might be a good reference :)