tests/helper-runtests.sh

test-obsolete-bundle-strip: test bundling in the fifth case

Updating all cases in the file at the same time is a bit overwhelming and harder
to double check. So each case come in its own patch.

#
# Avoid interference from actual test env:

unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL