UIntX.ofNatCore
UIntX.ofNat'
UIntX.ofNatLT
This PR unifies the existing functions `UIntX.ofNatCore` and `UIntX.ofNat'` under a new name, `UIntX.ofNatLT`.
This PR is a follow-up to #7057 and adds a builtin dsimproc for `UIntX.ofNatLT` which it turns out we need in stage0 before we can get the deprecation of `UIntX.ofNatCore` in favor of `UIntX.ofNatLT` off the ground.
UInt??.ofNatCore
UInt??.toNat
simproc
UInt