Just runs `tests/basic_test.sh -m` without building the snap
first. Useful for when you want to re-run the basic_test to verify
that a sporadic issue has been fixed, without rebuilding the snap each
Counterargument: you could always just run `tests/basic_test.sh -m` on
its own. I find it easier to keep one test command in my fingers,
however, rather than having to switch between "tox plus args" and
"something else plus args"