Add some integration tests for new [DoesNotReturn] feat

@kevin-montrose did a great job on it https://github.com/coverlet-coverage/coverlet/pull/904 and added also some tests

https://github.com/coverlet-coverage/coverlet/blob/master/test/coverlet.core.tests/Instrumentation/InstrumenterTests.cs#L647 https://github.com/coverlet-coverage/coverlet/blob/master/test/coverlet.core.tests/Samples/Instrumentation.DoesNotReturn.cs

We should add also some integration tests with same sample to cover also parameter option passed in(i.e. /p:DoesNotReturnAttribute="DoesNotReturnAttribute,OtherAttribute"):

1. Add a file https://github.com/coverlet-coverage/coverlet/tree/master/test/coverlet.core.tests/Coverage called CoverageTests.DoesNotReturn.cs
2. Add one test for every samples in file https://github.com/coverlet-coverage/coverlet/blob/master/test/coverlet.core.tests/Samples/Instrumentation.DoesNotReturn.cs

[daveMueller]

Ahh ok thanks. I didn’t check what happens in PrepareAttributes(...) 🙈. You can assign this to me then.

[MarcoRossignoli]

When using the samples in Instrumentation.DoesNotReturn.cs it doesn’t really make sense to pass a doesNotReturnAttribute to the instrumenter because it defaults to DoesNotReturnAttribute.

Yep we can for now avoid to add the attributes overload to test helper class, we use build-in DoesNotReturnAttribute