[llvm] [X86][CostModel] Add per-shape gather/scatter cost tables for AMD znver4+ (PR #199488)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

I'd like to add that the znver4 scheduler model has no gather/scatter overrides at all - that might be a better place to start.

https://github.com/llvm/llvm-project/pull/199488