do/while loop doesn't work.

Trying out a do/while loop I get this error.

```
[26] boris> do {
[26]     *>   $total += $i++;
[26]     *> } while($i <= 10);
PHP Parse error:  syntax error, unexpected end of file, expecting while (T_WHILE) in /Users/rodrigofigueroa1/.composer/vendor/d11wtq/boris/lib/Boris/EvalWorker.php(152) : eval()'d code on line 3
```
