Similar to what is done for the crypto WebWorker, we need to redirect console.{log,info,warn,error,trace} to a websocket back to xharness for testing purposes.

See

and

(note we don't want to set up the redirection on pthread creation - we want to do it when the worker that will run pthreads is created. Emscripten reuses workers to run pthreads when one thread shuts down and another one starts)