coverage needs to be started before importing the modules, so it can
not be started so late in runUnitTest, it has to be started before
importing any Products/ERP5* code, ie. in slapos wrapper script.

See https://coverage.readthedocs.io/en/6.5.0/faq.html#q-why-do-the-bodies-of-functions-show-as-executed-but-the-def-lines-do-not
for more details about the rationale