tests: in python tests, do not require .pyo files (for python3)

tests: in python tests, do not require .pyo files (for python3)

This change partially fixes automake bug#32088:
https://debbugs.gnu.org/32088

* t/py-compile-basedir.sh: Remove all .pyo checks.
Also, in this test only, allow for either 4 or 6 files resulting
from compilation, as new-enough Python3 results in 6
(per Andreas Huettel, https://debbugs.gnu.org/cgi/bugreport.cgi?bug=32088#17)
* t/py-compile-basic.sh: Remove all .pyo checks.
* t/py-compile-destdir.sh: Likewise.
* t/py-compile-option-terminate.sh: Likewise.
* t/python-virtualenv.sh: Likewise.
* t/python10.sh: Likewise.
* t/python12.sh: Likewise.
* t/python3.sh: Likewise.