[clang] [Clang] Add `noalias` to `this` pointer in C++ constructors (PR #136792)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

I just got a case:

```
class A {
public:
   class B {
   public:
         B(A *);

         // some non static data fields
   };

   B b(this);
};
```

Does this a valid prove that this optimization is not valid ?

https://github.com/llvm/llvm-project/pull/136792