IntegrationTests

TODO: Document this

Starting point: See .ado\windows-vs-pr.yml:
"Set up test servers" task
"Run Desktop Integration Tests" task

To debug locally
Run powershell script in "Setup test servers" task, eg
Start-TestServers.ps1 -SourcesDirectory D:\rnw_61\vnext -Preload -SleepSeconds 120
Open ReactWindows-Desktop.sln in Visual Studio
Build the solution
Open Test Explorer
Run React.Windows.Desktop.IntegrationTests