test_aportgen.py fails because some test data is missing.
Make the test pass by fixing the test data with the following changes:
- Update testdata pmaports/cross/*
- Don't git ignore test/testdata/aportgen directory
- Add testdata aports/main/* from upstream Alpine Linux aports

Patch files in pmaports/cross/binutils-armhf were removed, as they are
not needed to test the pmbootstrap code.