Generate protected accessor later in the pipeline

[allanrenucci]

Protected accessors are generated in SuperAccessors, while private accessors are generated much later in ExplicitOuter.

We'd like to move protected accessors later if possible (it makes it easier to move code around in later phases, and it means we don't have to pollute TASTY with the concept of protected accessors).

[allanrenucci]

Fixed in #4597