Tests: fix random failures on Zillion tests (#1128)

* tests: fix random failures on Zillion tests

Normally there's a low probably that the game doesn't require a power-up that it usually requires.
This makes sure it always has that requirement for tests.

* better type narrowing

test/worlds/zillion/__init__.py

@@ -1,5 +1,13 @@
 from test.worlds.test_base import WorldTestBase
+from worlds.zillion.region import ZillionLocation
 
 
 class ZillionTestBase(WorldTestBase):
     game = "Zillion"
+
+    def world_setup(self) -> None:
+        super().world_setup()
+        # make sure game requires gun 3 for tests
+        for location in self.world.get_locations():
+            if isinstance(location, ZillionLocation) and location.name.startswith("O-7"):
+                location.zz_loc.req.gun = 3