tests: fix up test-run-tests failures on Python 3.6
Some of the recent work on run-tests.py didn't work on Python 3. This
fixes the regressions.
Differential Revision: https://phab.mercurial-scm.org/D270
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true