ci: fix for `-autofree vlib/v/tests/option_test.v`

vlib/v/gen/c/cgen.v

@@ -2699,6 +2699,9 @@ fn (mut g Gen) autofree_var_call(free_fn_name string, v ast.Var) {
 	if v.typ.is_ptr() {
 		g.writeln('\t${free_fn_name}(${c_name(v.name)}); // autofreed ptr var')
 	} else {
+		if v.typ == table.error_type && !v.is_autofree_tmp {
+			return
+		}
 		g.writeln('\t${free_fn_name}(&${c_name(v.name)}); // autofreed var $g.cur_mod.name $g.is_builtin_mod')
 	}
 }