[clang] [Clang] Fix aggregate emitter assertion for Atomic cast (PR #207811)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

Is this fixing the same bug as https://github.com/llvm/llvm-project/pull/207616 (they're tracking two different issues, but the reproducers are almost identical)?

https://github.com/llvm/llvm-project/pull/207811