Fixed issue where `TestCase.setUpClass` is not called when a test has `/` in its name since pytest 6.2.0.

This refers to the path part in pytest node IDs, e.g. `TestClass::test_it` in the node ID `tests/test_file.py::TestClass::test_it`.

Now, instead of assuming that the test name does not contain ``/``, it is assumed that test path does not contain ``::``. We plan to hopefully make both of these work in the future.