Use coverage to short-circuit mutation

[ZevEisenberg]

A line with 0% coverage automatically has a mutation score of zero, so if we can detect that by looking at code coverage, we can automatically fail those lines without mutating them.

[Nikoloutsos]

@ZevEisenberg That sounds great and would definitely speed up the process 👍 Have you start any work on that?

[rakaramos]

this is already implemented