Fix bug with entities not being added from loaded chunks

No entities were lost in this bug, just we were triggering the add entities
before they were loaded due to an inconsistent order of putting chunk into chunkmap.

Any entity that appeared to be gone on the last build will now be back.

Spigot-Server-Patches/0320-Process-Chunk.addEntities-before-chunkLoadEvent.patch

@@ -1,4 +1,4 @@
-From 3413007c69032fcef8ac762e61f743b5c742df67 Mon Sep 17 00:00:00 2001
+From a4b33c025c22c73b86648dde212ee91c5942a9b6 Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Sun, 29 Jul 2018 16:56:48 -0400
 Subject: [PATCH] Process Chunk.addEntities before chunkLoadEvent
@@ -14,7 +14,7 @@ Moves Entity Add to World to be done anytime a chunk is
 registered to the Chunk Map, and ignore other calls.
 
 diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
-index 4e32ae7db..f0098e910 100644
+index 4e32ae7db6..f0098e910a 100644
 --- a/src/main/java/net/minecraft/server/Chunk.java
 +++ b/src/main/java/net/minecraft/server/Chunk.java
 @@ -897,7 +897,8 @@ public class Chunk implements IChunkAccess {
@@ -28,7 +28,7 @@ index 4e32ae7db..f0098e910 100644
          this.world.b(this.tileEntities.values());
          List[] aentityslice = this.entitySlices; // Spigot
 diff --git a/src/main/java/net/minecraft/server/ChunkMap.java b/src/main/java/net/minecraft/server/ChunkMap.java
-index 5757aa80f..c6cedba96 100644
+index 5757aa80f3..c6cedba96e 100644
 --- a/src/main/java/net/minecraft/server/ChunkMap.java
 +++ b/src/main/java/net/minecraft/server/ChunkMap.java
 @@ -31,6 +31,7 @@ public class ChunkMap extends Long2ObjectOpenHashMap<Chunk> {
@@ -39,8 +39,22 @@ index 5757aa80f..c6cedba96 100644
  
          org.bukkit.Server server = chunk.world.getServer();
          if (server != null) {
+diff --git a/src/main/java/net/minecraft/server/ChunkRegionLoader.java b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
+index bd52bf6561..e27e952a1b 100644
+--- a/src/main/java/net/minecraft/server/ChunkRegionLoader.java
++++ b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
+@@ -154,8 +154,8 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver {
+         if (data != null) {
+             Chunk chunk = (Chunk) data[0];
+             NBTTagCompound nbttagcompound = (NBTTagCompound) data[1];
+-            consumer.accept(chunk);
+             this.loadEntities(nbttagcompound.getCompound("Level"), chunk);
++            consumer.accept(chunk); // Paper - call AFTER entities are loaded
+             return chunk;
+         }
+ 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index ece187129..4fc3c2c35 100644
+index ece1871294..4fc3c2c354 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -2464,7 +2464,7 @@ public abstract class World implements GeneratorAccess, IIBlockAccess, AutoClose