go/format: turns correct program into incorrect one

go fmt changed the following correct Go program:

``` go
package main

func main() {
    x := 0 /**/; y := 1
    _, _ = x, y
}
```

into the following incorrect Go program:

```
package main

func main() {
    x := 0 /**/ y := 1
    _, _ = x, y
}
```
