Suspicious calls to `visitExpVoid`

[These](https://github.com/asgerf/tscheck/blob/master/tscheck.js#L2610) [three](https://github.com/asgerf/tscheck/blob/master/tscheck.js#L2801) [calls](https://github.com/asgerf/tscheck/blob/master/tscheck.js#L2802) to `visitExpVoid` either should be calls to `visitExp` or should not have a second argument (which `visitExpVoid` ignores).
