[llvm] [CostModel] Handle all cost kinds in getCmpSelInstrCost (PR #148233)

[Simon Pilgrim via llvm-commits]

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

LGTM - as a side note we should really try to cleanup more CostModel tests to use "-cost-kind=all"

https://github.com/llvm/llvm-project/pull/148233