[clang] [Clang][CodeGen] Emit load of GEP after EmitMemberExpr (PR #110487)

[Jan Hendrik Farr via cfe-commits]

Cydox wrote:

Wait, this introduces a regression when the inner struct is directly nested without using a pointer like so:

Without this change the code below will return 64, with my fix it will also return 64, with this fix it will SEGFAULT.

```C
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

struct variable {
        int a;
        int b;
        int length;
        short array[] __attribute__((counted_by(length)));
};

struct bucket {
        int a;
        struct variable growable;
//        struct variable *growable;
//        int b;
};

int main(int argc, char *argv[])
{
        struct bucket *p;
        struct variable *v;

        p = malloc(sizeof(*p) + sizeof(*p->growable.array) * 32);
        p->growable.length = 32;


//        printf("%zu\n", __builtin_dynamic_object_size(v->array, 1));

//        p->growable = v;
        printf("%zu\n", __builtin_dynamic_object_size(p->growable.array, 1));

        return 0;
}
```

https://github.com/llvm/llvm-project/pull/110487