[Helix] Enable Hosting.FunctionalTests

[HaoK]

Enable the following functional tests on helix:

Hosting/test/FunctionalTests/Microsoft.AspNetCore.Hosting.FunctionalTests.csproj
Servers/test/FunctionalTests/ServerComparison.FunctionalTests.csproj
Servers/Kestrel/test/Interop.FunctionalTests/Interop.FunctionalTests.csproj
DefaultBuilder/test/Microsoft.AspNetCore.FunctionalTests/Microsoft.AspNetCore.FunctionalTests.csproj
Mvc/test/Mvc.FunctionalTests/Microsoft.AspNetCore.Mvc.FunctionalTests.csproj

[natemcmaster]

Looks like this is one of many tests which will need to be refactored to work in Helix. cref #10268

[Pilchie]

@halter73 - we talked about you taking a look at this at some point, right?

[halter73]

We did. I haven't got a chance to look deeply into this yet, but it looks like #10268 is the current blocker.

My plate is already full for preview8, but I moved this out if the backlog into next spring planning. Is there any sort of deadline for this?