[clang] [clang]: support std::meta::info for primitive types (PR #190356)

[Nhat Nguyen via cfe-commits]

changkhothuychung wrote:

I just added mangling for reflection. With the support we have now, we can mangling the following 

```cpp
using info = decltype(^^int);

template <auto A>
void foo () {}

int main() {
  foo <info {}> ();
  foo <^^int> ();
  return 0;
}
```


Checked against gcc output: https://godbolt.org/z/PnqjdKMoo

https://github.com/llvm/llvm-project/pull/190356