tests: port test-wireproto.py to Python 3
A little bit of output churn because we now get b'' prefixes on output
in both 2 and 3, but for this test I'm more comfortable knowing that
we're using bytestrs everywhere.
Differential Revision: https://phab.mercurial-scm.org/D3510
.. Common link and substitution definitions.
.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html