[llvm] [CodeGen] Compact cost table entries (PR #202836)

[David Zbarsky via llvm-commits]

dzbarsky wrote:

> > (And please stop force-pushing, we don't do that here; commits are squashed and instead of rebasing, merge main.)
> 
> +1 to this - if you have a public WIP patch (to get early feedback) its fine to rebase while its in Draft form, but once its up for Rview, rebasing can affect comment history making it difficult to keep track of everything.

OK, will try to avoid it for this repo. In the past I've seen plenty of times github get confused when main is merged into a PR and display a massive diff, that's why I tend to rewrite the history :)

https://github.com/llvm/llvm-project/pull/202836