[clang] [Clang][CodeGen][CUDA] Add missing null-check assertions in CGCUDARuntime (PR #181167)

[Giovanni B. via cfe-commits]

Z3rox-dev wrote:

Thanks! Switched the explicit getAs<>() + assert checks to castAs<>() to encode the non-null contract more idiomatically. Updated the PR.

https://github.com/llvm/llvm-project/pull/181167