Made TestDiscoveryVisitor internal.
Added support for NuGet deployment of Visual Studio runner.
#9902: Handle xUnit.net v1 messages that don't some error elements (like timed out tests).
#9910: Data driven tests showing long, not short result, in VS Test runner.
#9901 & #9903: Temporary (?) hack to (mostly) re-enable CodeLens and individually runnable tests via keyboard.