Recently, the pytest script shipped by Fedora started invoking python
with the `-s` flag, which disables python considering user site
packages. This caused problems for our tests which install the cassandra
driver in the user site packages. This was worked around in e5e7780f32
by providing our own pytest interposer launcher script which does not
pass the above mentioned flag to python. Said patch fixed test.py but
not the run.py in cql-pytest. So if the cql-pytest suite is ran via
test.py it works fine, but if it is invoked via the run script, it fails
because it cannot find the cassandra driver. This patch patches run.py
to use our own pytest launcher script, so the suite can be run via the
run script as well.
Since run.py is shared with the alternator pytest suite, this patch also
fixes said test suite too.
Closes#12253
64903ba7d5