[llvm] [DebugInfo][NewGVN] Salvage debug values of trivially dead instructions (PR #149304)

[Orlando Cazalet-Hyams via llvm-commits]

https://github.com/OCHyams commented:

Are there are other calls to `markInstructionForDeletion` that should be accompanied by a salvage? What's the consequences of putting the salvage call in `markInstructionForDeletion` instead?

https://github.com/llvm/llvm-project/pull/149304