MC-99321 - Dont check for blocked double chest for hoppers etc

This is a source of MAJOR lag for hoppers, as well as a gameplay bug.

This removes the necessity to disable the cat on chest behavior to improve performance.

now performance will be improved even if you have cat chest detection on.

Spigot-Server-Patches/MC-99321-Dont-check-for-blocked-double-chest-for-hop.patch

@@ -0,0 +1,26 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Wed, 24 Jan 2018 20:06:39 -0500
+Subject: [PATCH] MC-99321 - Dont check for blocked double chest for hoppers
+ etc
+
+This is a source of MAJOR lag for hoppers, as well as a gameplay bug.
+
+This removes the necessity to disable the cat on chest behavior to improve performance.
+
+now performance will be improved even if you have cat chest detection on.
+
+diff --git a/src/main/java/net/minecraft/server/BlockChest.java b/src/main/java/net/minecraft/server/BlockChest.java
+index 90267a1fb..91d3308c1 100644
+--- a/src/main/java/net/minecraft/server/BlockChest.java
++++ b/src/main/java/net/minecraft/server/BlockChest.java
+@@ -0,0 +0,0 @@ public class BlockChest extends BlockTileEntity {
+                     // Paper end
+ 
+                     if (block == this) {
+-                        if (this.e(world, blockposition1)) {
++                        if (!flag && this.e(world, blockposition1)) { // Paper - check for allowBlocked flag - MC-99321
+                             return null;
+                         }
+ 
+--