[clang] [CodeGen] Fix cleanup attribute for C89 for-loop init variables (PR #156643)

[Jongmyeong Choi via cfe-commits]

jongmyeong-choi wrote:

I've implemented the change using a deferred cleanup approach.
Initially, I considered pushing cleanups to the EHStack while manipulating PrologueCleanupDepth, but I felt this approach was too hacky.
If there's a better approach for this fix, please let me know.

https://github.com/llvm/llvm-project/pull/156643