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

[Nhat Nguyen via cfe-commits]

changkhothuychung wrote:

> @changkhothuychung At this point, are you aware of anything that you still need to do for this patch? If not I believe we should go ahead and merge it soon so we can start implementing the rest of reflexion...

With what we have in this PR, it should be enough to proceed to the implementation of std::meta::is_type for primitive types. For unimplemented reflection entities in parsing, you will still get a diagnostics instead of a bool return from the function. Also, after this PR we should also be able to implement simple splice expressions, for example: 

```cpp
constexpr auto v = ^^int;
using type = [:v:];
static_assert(std::is_same_v<type, int>);
```


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