the "while" part of do-while loops should not share scope with the inner block

```ts
let a = 1;
do {
    let a = 2;
    console.log("a", a);
} while (a === 2);
```
https://typescripttolua.github.io/play.html#src=let%20a%20%3D%201%3B%0Ado%20%7B%0A%20%20%20%20let%20a%20%3D%202%3B%0A%20%20%20%20console.log(%22a%22%2C%20a)%3B%0A%7D%20while%20(a%20%3D%3D%3D%202)%3B%0A

We found [this issue with roblox-ts here](https://github.com/roblox-ts/roblox-ts/issues/292)