In order to run the shell system tests, the pytest runner has to pick
them up somehow. Adding an extra python file with a single function
for the shell tests for each system test proved to be the most
compatible way of running the shell tests across older pytest/xdist
versions.
Modify the legacy run.sh script to ignore these pytest-runner specific
glue files when executing tests written in pytest.
(cherry picked from commit 2f5bf6d971)
(manually added host/tests_sh_host.py, tkey/tests_sh_tkey.py on top)
3b6ca76f46