RFE: add "last known good" test BPF output to the tree for regression testing

[pcmoore]

We have some basic tooling to generate (tests/testgen) and compare (tests/testdiff) BPF output from multiple test runs, we should investigate adding known good BPF output from the tests to the tree to help catch problems with BPF generation.

These "known good" outputs will need to be maintained/updated as improvements are made to libseccomp, but the overhead shouldn't be prohibitive.