contrib: byteify perf.py file
This is done using contrib/byteify-strings.py. There is just one extra change
done to make sure lines don't get longer than 80 chars.
# skip-blame because just b'' prefixes.
Differential Revision: https://phab.mercurial-scm.org/D4422
warning
error
b'buffered\n'
colored? True
colored? True