[Issue 24257] ImportC: ICE on accessing last _Bool bitfield

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24257

--- Comment #2 from Dennis <dkorpel at live.nl> ---
Looks like dustmite found another bug by reducing away the star from the type.
Filed as issue 24259. Fixed test case:

```
typedef struct
{
    unsigned : 15;
    _Bool done : 1;
} S;

_Bool advance()
{
    S *n;
    if (n->done) {}
}
```

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