Always move Entity to its new Chunk even if unloaded

Vanilla logic here would allow us to remvoe an entity from
its current chunk, and if it was going to move into an unloaded
chunk, that entity would not be added to the unloaded chunk.

This is bad because this will result in the entity being lost!

In almost all cases, the chunk will be loaded, but in the event
it wasn't, instead of losing the entity, load the chunk to add
the entity to it.

Spigot-Server-Patches/Chunk-registration-fixes.patch

@@ -8,7 +8,7 @@ World checks and the Chunk Add logic are inconsistent on how Y > 256, < 0, is tr
 Keep them consistent
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 6e37c4366..000d2eeb9 100644
+index 6e37c4366..ea24a6e4c 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IBlockAccess {
@@ -20,4 +20,13 @@ index 6e37c4366..000d2eeb9 100644
          int k = MathHelper.floor(entity.locZ / 16.0D);
  
          if (!entity.aa || entity.ab != i || entity.ac != j || entity.ad != k) {
+@@ -0,0 +0,0 @@ public abstract class World implements IBlockAccess {
+                 this.getChunkAt(entity.ab, entity.ad).a(entity, entity.ac);
+             }
+ 
+-            if (!entity.bD() && !this.isChunkLoaded(i, k, true)) {
++            if (false && !entity.bD() && !this.isChunkLoaded(i, k, true)) { // Paper - Always send entities into a new chunk, never lose them
+                 entity.aa = false;
+             } else {
+                 this.getChunkAt(i, k).a(entity);
 --