[llvm] [AArch64] Enable UseFixedOverScalableIfEqualCost for more Cortex-x cpus. (PR #122807)

[Sjoerd Meijer via llvm-commits]

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

LGTM. If you're happy then I am happy too. :)
But more serious, I think this makes a lot of sense. It's still on my list to further look into this as I think there's more room for improvement, but I am happy to see more adoption. If this gets more adoption, we could maybe later discuss what the default should be. 

Maybe give it a day before merging to give @david-arm a chance to express his happiness or unhappiness. 

https://github.com/llvm/llvm-project/pull/122807