reproducible apks: strip file path prefix from .pyc files

[SomberNight]

Without this, paths from the build machine will leak into the generated .pyc files, which makes the builds more difficult to reproduce.

Note that the compileall -s option was only added in python 3.9. Not sure if that is acceptable, as this limits the hostpython3 recipe to 3.9+.

[AndreMiras]

Thanks for the pull request. Python 3.8 support ends the 31st of October 2024, refs https://endoflife.date/python and https://devguide.python.org/versions/ So I guess we're probably good to merge, but we need to tag a release before that. We will try to look this up