Dead Player's shouldn't be able to move

This fixes a lot of game state issues where packets were delayed for processing
due to 1.15's new queue but processed while dead.

Spigot-Server-Patches/Dead-Player-s-shouldn-t-be-able-to-move.patch

@@ -0,0 +1,22 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Thu, 2 Apr 2020 19:31:16 -0400
+Subject: [PATCH] Dead Player's shouldn't be able to move
+
+This fixes a lot of game state issues where packets were delayed for processing
+due to 1.15's new queue but processed while dead.
+
+diff --git a/src/main/java/net/minecraft/server/EntityHuman.java b/src/main/java/net/minecraft/server/EntityHuman.java
+index 584166f225..7afcde608e 100644
+--- a/src/main/java/net/minecraft/server/EntityHuman.java
++++ b/src/main/java/net/minecraft/server/EntityHuman.java
+@@ -0,0 +0,0 @@ public abstract class EntityHuman extends EntityLiving {
+ 
+     @Override
+     protected boolean isFrozen() {
+-        return super.isFrozen() || this.isSleeping();
++        return super.isFrozen() || this.isSleeping() || dead || !valid; // Paper - player's who are dead or not in a world shouldn't move...
+     }
+ 
+     @Override
+--