Remove cffi and add local_msg test

[slm960323]

• Remove cffi from the github action autotest
• Add task-bench to auto test
• Add local_msg test file
• Local_msg test failed with the current master

[ZwFink]

We should document that we are moving away from the CFFI and Ctypes backends, with Cython being the supported backend moving forward.

[slm960323]

Charm4Py is trying to move away from cffi and use the Cython as the default.

[rbuch]

These changes seem unrelated to each other, perhaps they should be different, more descriptive commits?

[rbuch]

If this repo should be used in CI, it should be under the UIUC-PPL organization or made part of the charm4py repo, I think.