tests/helper-runtests.sh

py3: do not reimplement Abort.__str__() on Python 2

It isn't necessary on Python 2, and the default implementation should be
better than our BaseException_str() clone.

#
# Avoid interference from actual test env:

unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL