[Issue 22966] Inconsistent `shared` attribute for generated destructor

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=22966

--- Comment #1 from kinke <kinke at gmx.net> ---
Trying to work around this with an explicit dummy ctor does NOT work:

```
struct WithDtor {
    int x;
    ~this() {}
}

struct A {
    WithDtor withDtor;
    ~this() shared {}
}

struct B {
    version (Shared)
        shared A a;
    else
        A a;
}

void main() {
    pragma(msg, A.__xdtor.mangleof);
}
```

```
$ dmd -o- foo.d
_D3mod1A10__aggrDtorMFZv
$ dmd -o- foo.d -version=Shared
_D3mod1A10__aggrDtorMOFZv
```

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