[clang] [llvm] [ci] New script to generate test reports as Buildkite Annotations (PR #113447)

[Louis Dionne via cfe-commits]

ldionne wrote:

Trying to understand what this patch does, basically it adds a summary when looking at the results of a BuildKite job?

Previously:
<img width="1924" alt="Screenshot 2024-10-24 at 13 00 24" src="https://github.com/user-attachments/assets/62dcabf5-414d-4c6b-928d-55df39ca02e0">

After this patch:
<img width="1920" alt="Screenshot 2024-10-24 at 13 00 47" src="https://github.com/user-attachments/assets/489bd367-496f-4222-8a64-c84396c1582c">

Basically, the sort of "plain text" report that gets added is the difference. Is that correct? Are there other differences (such as how test results get reported to Github actions)?

https://github.com/llvm/llvm-project/pull/113447