`@ptrFromInt(0)` on `?*allowzero T` gives null

### Zig Version

0.14.0-dev.1951+857383689

### Steps to Reproduce and Observed Behavior

```zig
comptime {
    @compileLog(@as(?*allowzero const u8, @ptrFromInt(0)));
}
```
```
Compile Log Output:
@as(?*allowzero const u8, null)
```
this feels very unexpected to me

### Expected Behavior

pointer should be the same as `@as(*allowzero const u8, @ptrFromInt(0))`