[llvm] [CodeGen] expand-fp: Change frem expansion criterion (PR #158285)

[Frederik Harwath via llvm-commits]

frederik-h wrote:

> I'm not sure about the costs but nothing is great for the cost of a libcall (I thought they were usually 10). The Arm/AArch64 changes look OK to me.

Thank you for the review @davemgreen!

https://github.com/llvm/llvm-project/pull/158285