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

[Louis Dionne via cfe-commits]

ldionne wrote:

FWIW, I didn't mean to derail this effort or create significant additional complexity by saying what I said above. My intention was only to point out the tradeoff of adding new functionality for a temporary benefit, which wasn't clear to me had been thought about in those terms.

I'd also be fine with proceeding with this approach as-is and then cleaning up the Lit flag in the future if we don't need it and if we think it won't break people (which is unlikely since that's a fairly niche flag). But @DavidSpickett you seem to have a firm understanding of what needs to happen and the various constraints, and you're clearly cognizant about adding tech debt, so at this point I'm personally very comfortable with deferring to your judgement for what's the best way to move forward.

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