[clang] [Clang] handle invalid close location in static assert declaration (PR #108701)

[Shafik Yaghmour via cfe-commits]

shafik wrote:

> > So this looks like a regression: https://gcc.godbolt.org/z/h6GexT18E
> 
> @shafik https://gcc.godbolt.org/z/Ebvnjrc8e

Interesting it crashes in trunk w/o `c++20`: https://gcc.godbolt.org/z/h9xa8eaqo but the backtrace looks the same.

We should test this in C++20 and C++23 as well then.

https://github.com/llvm/llvm-project/pull/108701