[Feature Request] Ability to get context switch information in a trace

The GC often needs context switch information to understand why GC threads were switched out, which lets them determine why a GC didn't complete quickly.

My hunch is that we'll need to do this with perfcollect because dotnet-trace/EventPipe doesn't have any OS kernel integration. However from the GC team they don't care too much what tool is needed to collect the trace as there is a way to do it.

cc @maoni0 @sywhang