py3: make contrib/testparseutil.py to work on str(unicodes) contrib/check-code work on unicodes and call functions from testparseutil.py which before this patch used to work on bytes. This path removes that inconsistency and make testparseutil.py work on unicodes. This makes test-check-code.t and test-contrib-check-code.t work on Python 3 again. Differential Revision: https://phab.mercurial-scm.org/D6391