Rollup merge of #125399 - scottmcm:less-hir-in-cg_ssa, r=compiler-errors

Stop using `to_hir_binop` in codegen

This came up in rust-lang/rust#125359 (comment) , and looking into it we can just use the `mir::BinOp`s directly instead of `hir::BinOpKind`s.

(AKA rather than going `mir::BinOp` → `hir::BinOpKind` → `IntPredicate`, just go `mir::BinOp` → `IntPredicate`.)