Make loaded entity list logic more consistent (#3301)

When adding/removing to a chunk, we need to also look at
editing the loaded entity list.

Co-authored-by: Spottedleaf <Spottedleaf@users.noreply.github.com>

Spigot-Server-Patches/0502-Optimize-entity-list-iteration-requiring-entities-be.patch

@@ -7,10 +7,34 @@ Subject: [PATCH] Optimize entity list iteration requiring entities be in
 We retain a list of loaded entities specifically for this usage
 
 diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
-index 750fb07756f7e40b21f8ab0925f2e842aae50f7b..69bfece7d43bc9e0c4cf7f71bffec9a44c2b9a67 100644
+index 750fb07756f7e40b21f8ab0925f2e842aae50f7b..21918ab101b423eadff5c00530f7a7c8e40cde9a 100644
 --- a/src/main/java/net/minecraft/server/Chunk.java
 +++ b/src/main/java/net/minecraft/server/Chunk.java
-@@ -801,6 +801,7 @@ public class Chunk implements IChunkAccess {
+@@ -588,6 +588,13 @@ public class Chunk implements IChunkAccess {
+         entity.chunkZ = this.loc.z;
+         this.entities.add(entity); // Paper - per chunk entity list
+         this.entitySlices[k].add(entity); if (entity.hardCollides()) this.hardCollidingEntities[k].add(entity); // Paper - optimise hard colliding entities
++        // Paper start - world loaded entity list
++        if (this.loadedTicketLevel) {
++            ((WorldServer)this.world).loadedEntities.add(entity);
++        } else {
++            ((WorldServer)this.world).loadedEntities.remove(entity);
++        }
++        // Paper end - world loaded entity list
+         // Paper start
+         if (entity instanceof EntityItem) {
+             itemCounts[k]++;
+@@ -627,6 +634,9 @@ public class Chunk implements IChunkAccess {
+         if (entity.hardCollides()) this.hardCollidingEntities[i].remove(entity); if (!this.entitySlices[i].remove(entity)) { // Paper - optimise hard colliding entities
+             return;
+         }
++        // Paper start - world loaded entity list
++        ((WorldServer)this.world).loadedEntities.remove(entity);
++        // Paper end - world loaded entity list
+         if (entity instanceof EntityItem) {
+             itemCounts[i]--;
+         } else if (entity instanceof IInventory) {
+@@ -801,6 +811,7 @@ public class Chunk implements IChunkAccess {
          this.setNeighbourLoaded(0, 0, this);
          this.loadedTicketLevel = true;
          // Paper end - neighbour cache
@@ -18,7 +42,7 @@ index 750fb07756f7e40b21f8ab0925f2e842aae50f7b..69bfece7d43bc9e0c4cf7f71bffec9a4
          org.bukkit.Server server = this.world.getServer();
          ((WorldServer)this.world).getChunkProvider().addLoadedChunk(this); // Paper
          if (server != null) {
-@@ -859,6 +860,7 @@ public class Chunk implements IChunkAccess {
+@@ -859,6 +870,7 @@ public class Chunk implements IChunkAccess {
          this.loadedTicketLevel = false;
          this.resetNeighbours();
          // Paper end