[win] delay process.exit when running on windows

This is super hacky but it might be worth including so we can focus on the other tests, and then circle back.
@krisselden @stefanpenner we actually don't need this hack anymore. We worked around it better by using https://www.npmjs.com/package/exit here: https://github.com/ember-cli/ember-cli/blob/master/bin/ember#L30 which works a lot like the code @krisselden linked to.