[llvm] [X86] Combine `uitofp <v x i32> to <v x half>` (PR #121809)

[via llvm-commits]

abhishek-kaushik22 wrote:

> Needs tests

I am not sure what to add in the tests. Should the tests include check-not for the inf constant or are auto-generated assertions enough? @RKSimon @arsenm 

https://github.com/llvm/llvm-project/pull/121809