Deterministic order for union typeguard generation

[jackTabsCode]

When using Flamework.createGuard<T> where T contains a union, that generated guard will sometimes change between compiles without a change in the source. This is undesirable behavior for me because I'm comparing the emit of typeguards in unit tests

[Fireboltofdeath]

Similar behavior also has to be implemented for user macro unions which are also currently not deterministic, the same machinery will likely be used for both user macros and type guards.

I'll likely have to revisit implementing user macro determinism, I did have a branch with the implementation previously but I wasn't happy with the performance of it so I shelved that version.