"Scoping Constructs" module needs testing gone over.

[rocky]

Description

Many of the doctests in Mathics3/mathics-core/mathics/builtin/scoping.py need going over and many should be converted to pytests when this isn't about documenting behavior. (Yes, we have still a lot of rot from the bad old days when Mathics developers didn't respect the difference between a doctest and a more conventional pytest or unit test)

See also https://github.com/Mathics3/mathics-core/pull/432