Implement a general test executor for all trace tools

[sywhang]

This is an issue to track a broad work item to implement a general test executor to help testing global tools for tracing (dotnet-counters, dotnet-trace) as well as LTTng.

Currently both dotnet-counters and dotnet-trace have tests, but not end-to-end testing. This is because the tests cannot be written in unit-test styles and has to be coordinated across two separate processes (the app being traced + the tool tracing the app). This applies to dotnet-counters, dotnet-trace, as well as LTTng.

Currently dotnet-dump already has SOSRunner, which is specific to SOS. The majority of this work can be reusing some of the components in SOSRunner (like ProcessRunner) and turn it into tracing coordinator.

With this in hand, we'll be able to automate full end-to-end testing for dotnet-counters, dotnet-trace, and LTTng.

[josalem]

This will be a good mechanism for comparing the event equivalence between ETW, EventPipe, and LTTng (when it makes sense). We have the individual components of the IPC mechanisms, event collection, counter collection, etc. covered pretty well, but this will add a unique coherence angle to our testing 👍