U+2028/U+2029 inside a multi-line comment leaves 2 stray bytes in emitted JS (invalid UTF-8)

## Steps to reproduce

Create `main.ts`:
```sh
printf '/* a\342\200\250b */ const x = 1;\n' > main.ts
```

```sh
tsgo --pretty false main.ts main.ts
```

## Behavior with `typescript@6.0`

```ts
"use strict";
/* a
b */ const x = 1;
```

## Behavior with `tsgo`

```ts
"use strict";
/* a�
b */ const x = 1;
```