Add no-deferred early break for gen3

c627a86f said it added for both 3 & 4, but was only added for gen4.

PKHeX.Core/Legality/Encounters/EncounterGenerator.cs

@@ -61,6 +61,9 @@ private static IEnumerable<IEncounterable> GetEncounters3(PKM pkm, LegalInfo inf
                 else
                     deferred.Add(z);
             }
+            if (deferred.Count == 0)
+                yield break;
+
             info.PIDIVMatches = false;
             foreach (var z in deferred)
                 yield return z;