[1.16] Make it run (#3626)

* She compiles!

Also readded the armorstand ticking patch, thanks cat

* Update mob goal api

* Misc fixes to make it run

drop per playing mob spawns for now

Spigot-Server-Patches/0350-Server-Tick-Events.patch

@@ -0,0 +1,32 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Wed, 27 Mar 2019 22:48:45 -0400
+Subject: [PATCH] Server Tick Events
+
+Fires event at start and end of a server tick
+
+diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
+index 6b288bc8d4153e12b35f422f171e15a2ef7d0851..060d64c207dc353d6103080f6756ac9501a4ed04 100644
+--- a/src/main/java/net/minecraft/server/MinecraftServer.java
++++ b/src/main/java/net/minecraft/server/MinecraftServer.java
+@@ -1120,6 +1120,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
+         });
+         isOversleep = false;MinecraftTimings.serverOversleep.stopTiming();
+         // Paper end
++        new com.destroystokyo.paper.event.server.ServerTickStartEvent(this.ticks+1).callEvent(); // Paper
+ 
+         ++this.ticks;
+         this.b(booleansupplier);
+@@ -1163,6 +1164,12 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
+         }
+         // Paper end
+ 
++        // Paper start
++        long endTime = System.nanoTime();
++        long remaining = (TICK_TIME - (endTime - lastTick)) - catchupTime;
++        new com.destroystokyo.paper.event.server.ServerTickEndEvent(this.ticks, ((double)(endTime - lastTick) / 1000000D), remaining).callEvent();
++        // Paper end
++
+         this.methodProfiler.enter("tallying");
+         long l = this.h[this.ticks % 100] = SystemUtils.getMonotonicNanos() - i;
+