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/0379-Do-not-accept-invalid-client-settings.patch

@@ -0,0 +1,24 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <Spottedleaf@users.noreply.github.com>
+Date: Sat, 7 May 2022 14:58:53 -0700
+Subject: [PATCH] Do not accept invalid client settings
+
+
+diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+index d2eb8c619905d87a38820a4c1179ad93093c0ac3..90e5f263dcb8033dae3ca32cbf5dbd332a109282 100644
+--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
++++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+@@ -3251,6 +3251,13 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
+     @Override
+     public void handleClientInformation(ServerboundClientInformationPacket packet) {
+         PacketUtils.ensureRunningOnSameThread(packet, this, this.player.serverLevel());
++        // Paper start - do not accept invalid information
++        if (packet.information().viewDistance() < 0) {
++            LOGGER.warn("Disconnecting " + this.player.getScoreboardName() + " for invalid view distance: " + packet.information().viewDistance());
++            this.disconnect(Component.literal("Invalid client settings"), org.bukkit.event.player.PlayerKickEvent.Cause.ILLEGAL_ACTION);
++            return;
++        }
++        // Paper end - do not accept invalid information
+         this.player.updateOptions(packet.information());
+         this.connection.channel.attr(io.papermc.paper.adventure.PaperAdventure.LOCALE_ATTRIBUTE).set(net.kyori.adventure.translation.Translator.parseLocale(packet.information().language())); // Paper
+     }