selftests: Make test_harness.h more generally available

The seccomp/test_harness.h file contains useful helpers to build tests.
Moving it to the selftest directory should benefit to other test
components.

Keep seccomp maintainers for this file.
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Drewry <wad@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Shuah Khan <shuah@kernel.org>
Link: https://lkml.kernel.org/r/CAGXu5j+8CVz8vL51DRYXqOY=xc3zuKFf=PTENe88XYHzFYidUQ@mail.gmail.comSigned-off-by: Shuah Khan <shuahkh@osg.samsung.com>

MAINTAINERS

@@ -11495,6 +11495,7 @@ F:	kernel/seccomp.c
 F:	include/uapi/linux/seccomp.h
 F:	include/linux/seccomp.h
 F:	tools/testing/selftests/seccomp/*
+F:	tools/testing/selftests/kselftest_harness.h
 K:	\bsecure_computing
 K:	\bTIF_SECCOMP\b
 

tools/testing/selftests/seccomp/seccomp_bpf.c

@@ -37,7 +37,7 @@
 #include <unistd.h>
 #include <sys/syscall.h>
 
-#include "test_harness.h"
+#include "../kselftest_harness.h"
 
 #ifndef PR_SET_PTRACER
 # define PR_SET_PTRACER 0x59616d61