Remove dummy test infrastructure and its dependencies

[DoctorKrolic]

These dummy test infrastructure doesn't bring any value, but adds several dependencies that need to be taken care of (security updates and so on). So I think we better follow You aren't gonna need it principle and remove this ballast all together. We can always revert this change if we ever need to. @tintoy Would like your approval on this

Closes https://github.com/tintoy/msbuild-project-tools-vscode/pull/107 Closes https://github.com/tintoy/msbuild-project-tools-vscode/pull/106 Closes https://github.com/tintoy/msbuild-project-tools-vscode/pull/100

[tintoy]

Thanks!