Add integration tests for the ApiCompat global tool

[ViktorHofer]

The Microsoft.DotNet.ApiCompat.Tool global currently doesn't have any integration tests. Also, the ConsoleLog type in it is currently completely untested. We should add test coverage for that.

[dotnet-policy-service]

@dotnet/area-infrastructure-libraries a new issue has been filed in the ApiCompat area, please triage