[clang] [CodeGen] Set attributes on coroutine wrapper functions (PR #207961)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-x86_64-debian-dbg-bootstrap-build` running on `libc-x86_64-debian` while building `clang` at step 3 "checkout".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/200/builds/33206

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 3 (checkout) failure: update (failure)
git version 2.39.5
remote: This request was rate-limited due to too many requests. Reduce the frequency of your requests or try again later.
remote: For more on scraping GitHub and how it may affect your rights, please review our Terms of Service (https://docs.github.com/en/site-policy/github-terms/github-terms-of-service).
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': The requested URL returned error: 429
remote: This request was rate-limited due to too many requests. Reduce the frequency of your requests or try again later.
remote: For more on scraping GitHub and how it may affect your rights, please review our Terms of Service (https://docs.github.com/en/site-policy/github-terms/github-terms-of-service).
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': The requested URL returned error: 429

```

</details>

https://github.com/llvm/llvm-project/pull/207961