Refactor the test logic. Seccomp tests that can be
killed run in their own subprocess now.
All test functions now return 0 on success. Therefore,
the shell script can be simplified.
Instead of having a blacklist and whitelist, we now allow
setting a policy that runs as a chain.
This adds qssb_append_syscalls_policy()
Furthermore, add a feature to decide per syscall which action to take.
This allows now to return an error instead of just killing the process.
In the future, it may allow us to set optimize/shrink the BPF filter.
The arch field is the same for x86_64 and x32, thus checking it
is not enough.
Simply using x32 system calls would allow a bypass. Thus,
we must check whether the system call number is in __X32_SYSCALL_BIT.
This is of course a lazy solution, we could also add the
same system call number + _X32_SYSCALL_BIT to our black/whitelists.
For now however, this however will do.
