Integration tests: aux_bin_paths fixture causes running a single test to take too long

[alxiord]

The aux_bin_paths fixture builds other binaries used in the integration test suite:

• a binary that clones into the jailer, because Python doesn't clone into native C seamlessly
• vsock test binary
• seccomp test binaries: harmless and malicious jailers and jailed processes

The vsock binary is only relevant in vsock tests. The seccomp binaries are only relevant in seccomp tests. However, the cloner is needed in every test, so the fixture that builds all these binaries is a dependency to all the tests. This leads to a very common problem in the development process: a developer builds a feature, writes an integration test for it, and runs just that test, but still gets all these extra unnecessary binaries - that also take long to build.

The aux_bin_paths fixture should be split (back) in multiple specialized fixtures.