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

[Florian Hahn via llvm-commits]

fhahn wrote:

> > 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.

Moved there, as it is overall a bit more compact when used outside Instruction:: :) 

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