[llvm] [VectorCombine] Pull out TargetCostKind argument to allow globally set cost kind value (PR #118652)

[David Green via llvm-commits]

https://github.com/davemgreen commented:

Sounds OK to me. Did you consider making it a class member, to avoid all the extra args to the fold functions?

https://github.com/llvm/llvm-project/pull/118652