[llvm] [LV] Stop using the legacy cost model for udiv + friends (PR #152707)

[Luke Lau via llvm-commits]

lukel97 wrote:

I checked this out locally and can confirm this fixes https://github.com/llvm/llvm-project/issues/154103, and it also builds llvm-test-suite + SPEC CPU 2017 without crashing. I can commit the test case for #154103 after this lands

https://github.com/llvm/llvm-project/pull/152707