[llvm] [IR] Provide array with poison-generating metadata IDs. (PR #123188)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

> Add Instruction::PoisonGeneratingMetadataIDs containing IDs of poison-generating metadata to allow easier re-use.
> 
> Currently it is a static const array in Instruction, maybe here's a better place?

`Metadata::PoisonGeneratingIDs` maybe? No strong opinion.

https://github.com/llvm/llvm-project/pull/123188