Remove wall-time / unused skip tick protection (#11412)

Spigot still maintains some partial implementation of "tick skipping", a
practice in which the MinecraftServer.currentTick field is updated not
by an increment of one per actual tick, but instead set to
System.currentTimeMillis() / 50. This behaviour means that the tracked
tick may "skip" a tick value in case a previous tick took more than the
expected 50ms.

To compensate for this in important paths, spigot/craftbukkit
implements "wall-time". Instead of incrementing/decrementing ticks on
block entities/entities by one for each call to their tick() method,
they instead increment/decrement important values, like
an ItemEntity's age or pickupDelay, by the difference of
`currentTick - lastTick`, where `lastTick` is the value of
`currentTick` during the last tick() call.

These "fixes" however do not play nicely with minecraft's simulation
distance as entities/block entities implementing the above behaviour
would "catch up" their values when moving from a non-ticking chunk to a
ticking one as their `lastTick` value remains stuck on the last tick in
a ticking chunk and hence lead to a large "catch up" once ticked again.

Paper completely removes the "tick skipping" behaviour (See patch
"Further-improve-server-tick-loop"), making the above precautions
completely unnecessary, which also rids paper of the previous described
incompatibility with non-ticking chunks.

patches/server/0726-Custom-Chat-Completion-Suggestions-API.patch

@@ -0,0 +1,35 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
+Date: Sat, 30 Jul 2022 11:23:05 -0400
+Subject: [PATCH] Custom Chat Completion Suggestions API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index 7f47005c08cccbcb8cd5ac56157c4e0d0dfe10b0..3374dcd3b1f22b6c1803b9580c4cea6552b6afb1 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -691,6 +691,24 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+     }
+     // Paper end - Add sendOpLevel API
+ 
++    // Paper start - custom chat completions API
++    @Override
++    public void addAdditionalChatCompletions(@NotNull Collection<String> completions) {
++        this.getHandle().connection.send(new net.minecraft.network.protocol.game.ClientboundCustomChatCompletionsPacket(
++            net.minecraft.network.protocol.game.ClientboundCustomChatCompletionsPacket.Action.ADD,
++            new ArrayList<>(completions)
++        ));
++    }
++
++    @Override
++    public void removeAdditionalChatCompletions(@NotNull Collection<String> completions) {
++        this.getHandle().connection.send(new net.minecraft.network.protocol.game.ClientboundCustomChatCompletionsPacket(
++            net.minecraft.network.protocol.game.ClientboundCustomChatCompletionsPacket.Action.REMOVE,
++            new ArrayList<>(completions)
++        ));
++    }
++    // Paper end - custom chat completions API
++
+     @Override
+     public void setCompassTarget(Location loc) {
+         Preconditions.checkArgument(loc != null, "Location cannot be null");