`Enzyme.ReverseSplitWithPrimal` is not supported

```julia
using Enzyme, Reactant

f(x) = sum(abs2, x .* x)

function enzyme_split_mode(x)
dx = Enzyme.make_zero(x)
forward, reverse = autodiff_thunk(
ReverseSplitWithPrimal, Const{typeof(f)}, Active, Duplicated{typeof(x)}
)
tape, result, shadow_result = forward(Const(f), Duplicated(x, dx))
reverse(Const(f), Duplicated(x, dx), 1.0, tape)
return result, dx
end

x = rand(10)

f(x)
enzyme_split_mode(x)

x_ra = Reactant.to_rarray(x)

@code_hlo optimize = true enzyme_split_mode(x_ra)
```