[clang] [Clang] Handle consteval expression in array bounds expressions (PR #66222)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

I think this generally makes a lot of sense, I have 1 nit (plus a bunch of the 'bool' comments without the = sign that @shafik suggested, but were closed without comment), otherwise LGTM.

https://github.com/llvm/llvm-project/pull/66222