selftests/seccomp: Be more precise with syscall arguments.

Certain syscall emulation layers strictly check that the number of
arguments match what the syscall handler expects. The KILL_one_arg_one and
KILL_one_arg_six tests passed more parameters than expected to various
syscalls, causing failures in this emulation mode. Instead, test using
syscalls that take the appropriate number of arguments.

Signed-off-by: Robert Sesek <rsesek@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>