2022-February-14 - Prerelease - 2.6.572

Preserve polygon order when loading game. (#9963)

This is critical for "island" situations when one territory completely encloses another. By using hash map in this class, the "z order" of the territories is totally unpredictable. This affects our map because we use rail road zones (sea zones) inside land zones and we want to make sure they, and the units in them, are always selectable "above" the containing land territory.