Trade cleanup (#4971)

* Move adult trade to flags

* Move child trade to flags

* Fix vanilla

* Address review

* Rename `trade_shuffle` to `ShuffleTradeItems`

* Fix mac build

* Update GIVanillaBehavior.h

* Update z_kankyo.c

* Update z_en_heishi2.c

soh/include/z64save.h

@@ -160,7 +160,6 @@ typedef struct {
 #pragma region SoH
 
 typedef struct ShipRandomizerSaveContextData {
-    u16 adultTradeItems;
     u8 triforcePiecesCollected;
 } ShipRandomizerSaveContextData;