LttP: fix multithreading racing condition resulting in Ganon giving the wrong prog bow hint, also have one less world.find_items() which is quite cpu expensive

worlds/alttp/__init__.py

@@ -51,6 +51,7 @@ class ALTTPWorld(World):
         self.dungeon_local_item_names = set()
         self.dungeon_specific_item_names = set()
         self.rom_name_available_event = threading.Event()
+        self.has_progressive_bows = False
         super(ALTTPWorld, self).__init__(*args, **kwargs)
 
     def generate_early(self):