[clang] [Clang] Fix deduction from constant TP of reference type. (PR #223645)

[via cfe-commits]

eaeltsin wrote:

This commit seems to break template template argument matching (`[temp.arg.template]` p3–4) when a template parameter is a non-type template parameter of dependent reference type:
```cpp
template <template <auto&> class> struct Outer;
template <template <auto&> class Inner>
using T = Outer<Inner>;
```
```text
<stdin>:2:34: error: could not match 'auto &' against 'auto'
```
https://godbolt.org/z/fhG9qKqYn

https://github.com/llvm/llvm-project/pull/223645