[llvm] [GlobaISel] Allow expanding of sdiv -> mul by constant (PR #146504)

[David Green via llvm-commits]

https://github.com/davemgreen commented:

This looks OK to me from what I can tell and everyone else isn't against it. I noticed that we didn't have a lot of tests for scalar sdiv that changed, only vector versions. Can we make sure there are some scalar tests?

https://github.com/llvm/llvm-project/pull/146504