[clang] [Clang] Add __builtin_is_within_lifetime to implement P2641R4's std::is_within_lifetime (PR #91895)

[Mital Ashok via cfe-commits]

MitalAshok wrote:

@cor3ntin A `void*` can be a pointer to an object but `void*` is not a pointer-to-object type. `is_object_v<T>` -> `is_object_v<T> || is_void_v<T>` or `!is_function_v<T>`

https://github.com/llvm/llvm-project/pull/91895