tests: consistently use pyflakes as a Python module
We check availability of pyflakes as a module, and also running it for real as
a module. Only fair to test filterpyflakes.py working correctly when using
pyflakes as a module too.
This is a graft of a similar fix that ended up on default.
Differential Revision: https://phab.mercurial-scm.org/D8629
# Balto (https://bitbucket.org/lothiraldan/balto/src) is a test orchestrator
# which is compatible with all test runner that can emit the LITF
# (https://github.com/lothiraldan/litf) test format.
# The plugin for the Mercurial test runner is mercurial-litf
# (https://pypi.org/project/mercurial-litf/). Make sure to follow the
# instruction and configuration instructions here:
# https://bitbucket.org/lothiraldan/mercurial_litf/src/default/
# You can launch Balto with `balto /path/to/mercurial/tests/`
name = "Mercurial Test Suite"
tool = "mercurial"