Newline character literal with unicode-escaped single quotes incorrectly parses as single-quote character constant

As asked/discussed in https://stackoverflow.com/q/74363301/40342 the following code incorrectly prints `true` when compiled with ECJ (verified with versions 3.19.0 to 3.32.0, earlier versions untested):

```
public class QuoteBug {
static void main(String... args) {
char e = \u0027\n\u0027;
char f = '\'';
System.out.println(e == f);
}
}
```

Using the OpenJDK `javac` this correctly prints `false` as `e` and `f` have the values 10 and 39 respectively, whereas ECJ assignes both variables the value 39.