selftests/seccomp: Set NNP for TSYNC ESRCH flag test

The TSYNC ESRCH flag test will fail for regular users because NNP was
not set yet. Add NNP setting.

Fixes: 51891498 ("seccomp: allow TSYNC and USER_NOTIF together")
Cc: stable@vger.kernel.org
Reviewed-by: Tycho Andersen <tycho@tycho.ws>
Signed-off-by: Kees Cook <keescook@chromium.org>

tools/testing/selftests/seccomp/seccomp_bpf.c

@@ -3262,6 +3262,11 @@ TEST(user_notification_with_tsync)
 	int ret;
 	unsigned int flags;
 
+	ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+	ASSERT_EQ(0, ret) {
+		TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
+	}
+
 	/* these were exclusive */
 	flags = SECCOMP_FILTER_FLAG_NEW_LISTENER |
 		SECCOMP_FILTER_FLAG_TSYNC;