selftests/seccomp: allow clock_nanosleep instead of nanosleep

glibc 2.31 calls clock_nanosleep when its nanosleep function is used. So
the restart_syscall fails after that. In order to deal with it, we trace
clock_nanosleep and nanosleep. Then we check for either.

This works just fine on systems with both glibc 2.30 and glibc 2.31,
whereas it failed before on a system with glibc 2.31.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>