Invoke pytest runner from run.sh

Utilize developers' muscle memory to incentivize using the pytest runner
instead of the legacy one. The script also serves as basic examples of
how to run the pyest command to achieve the same results as the legacy
runner.

Invoking pytest directly should be the end goal, since it offers many
potentially useful options (refer to pytest --help).

bin/tests/system/get_algorithms.py

@@ -230,7 +230,7 @@ def main():
     except Exception:
         # if anything goes wrong, the conf.sh ignores error codes, so make sure
         # we set an environment variable to an error value that can be checked
-        # later by run.sh
+        # later by the test runner and/or tests themselves
         print("export ALGORITHM_SET=error")
         raise
     for name, value in algs_env.items():