Add tests for seccomp() syscall

[metan-ucw]

We do have some of the seccomp() functionality covered in prctl() tests, but we have no test that would test the seccomp() syscall itself and there is no coverage for the user space notification.

There is a nice example to be added to manual pages here:

https://lwn.net/Articles/833128/

[treedavies]

I'm taking on this task.

[pevik]

Note from #290: The seccomp call gained support for userspace notifications see: https://lwn.net/Articles/776035/#userspace

[coolgw]

checking.

[coolgw]

https://patchwork.ozlabs.org/project/ltp/patch/[email protected]/

[coolgw]

This need v2 version, i will continue work on this.

[acerv]

I'm wondering if we need this, since kselftests already have an extensive testing suite around eBPF seccomp() filtering and prctl() testing suite has already tests for it.

[coolgw]

So i hold my action.