[clang] [llvm] [Pipelines][Coroutines] Tune coroutine passes only for ThinLTO pre-link pipeline (PR #90690)

[Sam Clegg via cfe-commits]

https://github.com/sbc100 approved this pull request.

I'm not very familiar with this code, but it looks reasonable on the surface.

https://github.com/llvm/llvm-project/pull/90690