Run mypyc tests against built wheels (#11865)
This should catch https://github.com/mypyc/mypyc/issues/912
We never ran mypyc tests against wheels, dating back to https://github.com/python/mypy/tree/783297c9b4ed3b2af9000c3536d6e1be34fed9ea/misc
Co-authored-by: hauntsaninja <>
