Use RuntimeGeneratedFunctions.jl instead of eval

[dpsanders]

https://github.com/SciML/RuntimeGeneratedFunctions.jl

[dpsanders]

https://discourse.julialang.org/t/modelingtoolkit-intervalconstraintprogramming-how-to-build-expressions-and-contractors-without-world-age-problems-or-ambiguities/59007/3

[aafsar]

I had a quick look at this. RuntimeGeneratedFunctions.jl doesn't work with closures. So I guess:

• either this part of code_generation.jl needs to be rewritten,
• or GeneralizedGenerated.jl can be used instead. But it constructs its own callable type which is not a subtype of Function. Thus if this to be implemented, the definition of Contractor/Basic Contractor needs to be adjusted accordingly.

I'm not sure which one is better though.