[clang] [CodeGenTypes] Preserve element type attributes within a `ConstantArrayType` (PR #211978)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic requested changes to this pull request.

Please fix the representation of matrix types in the AST so the layout doesn't depend on type sugar.

https://github.com/llvm/llvm-project/pull/211978