[clang] [mlir] [CIR] Implement 'noreturn' attribute for functions/calls. (PR #177978)

[Andrzej Warzyński via cfe-commits]

https://github.com/banach-space approved this pull request.

MLIR LGTM, thanks! Deferring Clang  IR part to Andy.

https://github.com/llvm/llvm-project/pull/177978