tests/valgrind: add skipped fn_returning_string_param.vv (-autofree)

vlib/v/tests/valgrind/fn_returning_string_param.vv

@@ -0,0 +1,13 @@
+fn identity(s string) string {
+	return s
+}
+
+fn main() {
+	sa := 'abc'
+	sb := 'def'
+	sc := sa + sb
+	sd := identity(sc)
+	if sc != sd {
+		exit(1)
+	}
+}

vlib/v/tests/valgrind/valgrind_test.v

@@ -7,6 +7,7 @@ import v.util.vtest
 const (
 	skip_valgrind_files = [
 		'vlib/v/tests/valgrind/struct_field.vv',
+		'vlib/v/tests/valgrind/fn_returning_string_param.vv',
 	]
 )