`VAR_IN_OUT` does not behave as expected when dealing with `ARRAY OF STRING`

```
FUNCTION foo
VAR_IN_OUT 
    in : ARRAY[0..1] OF STRING;
END_VAR
    in[0] := 'hello';
    in[1] := 'world';
END_FUNCTION

FUNCTION main
VAR bar : ARRAY[0..1] OF STRING; END_VAR
    foo(bar);
    printf('%s %s$n', REF(bar[0]), REF(bar[1]));
END_FUNCTION
```

When running the above example, the printed result is `hworld`, when it should be `hello world`.