CSharp/* Remove TE dependencies (#3529)
* [ci lang-only CSharp] CSharp/* Remove TE dependencies
I can't tell if this is changing the version of aspnetcore that we're
using, but it's the same docker dependency that the aspnet/benchmarks
GitHub project uses, so that's probably what we should use too:
https://github.com/aspnet/benchmarks/blob/500d8b0990afdbe9ccd329191b8a93df9b5524bf/docker/benchmarks/Dockerfile#L1
* [ci lang-only CSharp] fix aspnetcore-mvc dockerfile