[clang] [llvm] [clang][CUDA] Allow `extern __shared__` on non-array types (PR #183879)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

Could you add a `NOTE: Do not autogenerate` comment explaining that these checks focus on shared types and accesses, or generate them with the Clang test updater?

https://github.com/llvm/llvm-project/pull/183879