Incorrect type of token with number 0xFFFF because of incorrect ATN serialization

### Grammar

```g4
lexer grammar L;
T_FFFF: 'FFFF' -> type(65535);
```

### Input

```
FFFF
```

### Actual result

```g4
[@0,0:3='FFFF',<-1>,1:0]
```

But `-1` value is reserved for `EOF`

### Expected result

```g4
[@0,0:3='FFFF',<65535>,1:0]
```