These tests don't seem to specifically test GC, so it doesn't seem to be a good comparison.

Comparing Go and C# as languages don't seem to be the goal of this exercise, either. Instead, the article was making the point that the garbage characteristics have generational components. This is true of C#, so I would expect it to be true of Go as well. If that is the case, whatever Go's current performance numbers are, they could probably be made better by a generational GC.