MultiFileSolutionAndProjectTests skipped

MultiFileSolutionAndProjectTests are currently skipped until someone can find the right SDK setup for the build agent to build them again. They're a bit finnicky because they intentionally try to build old versions of projects to ensure support for people trying to move legacy apps. It may be necessary to just point them at a later, or the latest version of the SDK. Anything is better than just not running them at all.