4092: feat: run ignored tests r=matklad a=hdevalke
I started making some exercices on https://exercism.io/ and a lot of test have the `#[ignore]` attribute.
The `Run Test|Debug` code lens show up, but running the test results in:
```
running 1 test
test test_one_piece ... ignored
test result: ok. 0 passed; 0 failed; 1 ignored; 0 measured; 5 filtered out
```
This pull request adds the `--ignored` flag if needed.
Co-authored-by: Hannes De Valkeneer <hannes@de-valkeneer.be>
604b936ca0