Crashes when starting experimental instance aren't captured

[davidwengier]

Had a misconfiguration in an extension (binding redirect for a DLL that wasn't being deployed) which meant the experimental instance crashed immediately on startup. The error was in the Activity Log but the experience of running the tests was just that they hung because IntegrationHelper.TryLocateDteForProcess has no timeout.

Would be good to have a timeout around https://github.com/microsoft/vs-extension-testing/blob/main/src/Microsoft.VisualStudio.Extensibility.Testing.Xunit.Shared/Harness/VisualStudioInstanceFactory.cs#L148