[Mono-dev] [CI] RFC - Mono now building on Cygwin/Windows with Appveyor

[Vincent Povirk]

> - I'd also like to run the Mono tests as a part of the build
> verification. Are they expected to work under Windows/Cygwin?

I was not able to run the tests on Windows/Mono in current master. I
made this PR to address that: https://github.com/mono/mono/pull/1360

They should run on Windows/.NET without that patch.

I don't expect them to pass, even on .NET, and I think it'd be a large
effort to whip them into shape.