Don't unwrap and re-wrap streams (#1969)
Unwrapping and re-wrapping stdout and stderr after setup and before the main
loop seems to cause weird errors with some models. Specifically, models that
work by launching a subprocess (such as fofr/cog-comfyui) get into a broken
state when we do this.
It's possible that there's a way to do the unwrapping that doesn't break these
models but I'm unsure how we do that.
