Revert "Fix stop_on_error_timeout blocking other messages in queue"

[afshin]

Running git bisect and pytest papermill/tests/test_execute.py::TestBrokenNotebook1::test showed that the error in #568 comes from #539. The message returned from kernel_info_request has status aborted. We are reverting the change to prevent downstream breakage. cc @glentakahashi we can revisit your changes in a follow up if you like, making sure that we better understand its ramifications.

self = <papermill.clientwrap.PapermillNotebookClient object at 0x7fc060ea5b20>, kwargs = {}
info_msg = {'buffers': [], 'content': {'status': 'aborted'}, 'header': {'date': datetime.datetime(2020, 12, 11, 20, 27, 58, 67808...bc689097e1e214f38609b', ...}, 'metadata': {'engine': '0d33e2cb-93c6-4480-983f-70f97a54b86d', 'status': 'aborted'}, ...}

Reverts #539