selftests: arg_parsing: Ensure data is flushed to disk before reading.

Thanks for reviewing! Here's the revised patch.

Author: higuoxing

tools/testing/selftests/bpf/prog_tests/arg_parsing.c

@@ -140,9 +140,11 @@ static void test_parse_test_list_file(void)
 	fprintf(fp, "testA/subtest2\n");
 	fprintf(fp, "testC_no_eof_newline");
 	fflush(fp);
-
-	if (!ASSERT_OK(ferror(fp), "prepare tmp"))
-		goto out_fclose;
+	if (!ASSERT_OK(ferror(fp), "prepare tmp")) {
+		fclose(fp);
+		goto out_remove;
+	}
+	fclose(fp);
 
 	init_test_filter_set(&set);
 
@@ -160,8 +162,6 @@ static void test_parse_test_list_file(void)
 
 	free_test_filter_set(&set);
 
-out_fclose:
-	fclose(fp);
 out_remove:
 	remove(tmpfile);
 }