Move up harv.IsEmpty check in HackyAI

This is a fairly cheap check, so we should perform it before the activity checks

OpenRA.Mods.Common/AI/HackyAI.cs

@@ -820,6 +820,9 @@ namespace OpenRA.Mods.Common.AI
 				if (harv == null)
 					continue;
 
+				if (!harv.IsEmpty)
+					continue;
+
 				if (!harvester.IsIdle)
 				{
 					var act = harvester.CurrentActivity;
@@ -827,9 +830,6 @@ namespace OpenRA.Mods.Common.AI
 						continue;
 				}
 
-				if (!harv.IsEmpty)
-					continue;
-
 				// Tell the idle harvester to quit slacking:
 				var newSafeResourcePatch = FindNextResource(harvester, harv);
 				BotDebug("AI: Harvester {0} is idle. Ordering to {1} in search for new resources.".F(harvester, newSafeResourcePatch));