[llvm] [HLSL] Refactoring DXILABI.h to not depend on scope printer (PR #153840)

[Damyan Pepper via llvm-commits]

damyanp wrote:

Another alternative would be to fix the (I think) 3 cases of misused `to_underlying` that are modified in this PR, and subsequently fix all the others.

https://github.com/llvm/llvm-project/pull/153840