selftests/bpf: Add support for marking sub-tests as skipped

Previously skipped sub-tests would be counted as passing with ":OK" appened
in the log. Change that to be accounted as ":SKIP".
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-8-andrii@kernel.org

tools/testing/selftests/bpf/test_progs.c

@@ -149,15 +149,15 @@ void test__end_subtest()
 
 	if (sub_error_cnt)
 		env.fail_cnt++;
-	else
+	else if (test->skip_cnt == 0)
 		env.sub_succ_cnt++;
 	skip_account();
 
 	dump_test_log(test, sub_error_cnt);
 
 	fprintf(env.stdout, "#%d/%d %s:%s\n",
-	       test->test_num, test->subtest_num,
-	       test->subtest_name, sub_error_cnt ? "FAIL" : "OK");
+	       test->test_num, test->subtest_num, test->subtest_name,
+	       sub_error_cnt ? "FAIL" : (test->skip_cnt ? "SKIP" : "OK"));
 
 	free(test->subtest_name);
 	test->subtest_name = NULL;