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/0024-Further-improve-server-tick-loop.patch

@@ -12,7 +12,7 @@ Previous implementation did not calculate TPS correctly.
 Switch to a realistic rolling average and factor in std deviation as an extra reporting variable
 
 diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
-index d76dae9ce9022308b316080ac48b7030d674cc6b..e9d56d75b7c648f04d3a56942b2866090c570129 100644
+index 49de4625c57689a3624ed421c0b03512507c97c3..46e03617bb32e4037d700c1b3698d397bd75de5c 100644
 --- a/src/main/java/net/minecraft/server/MinecraftServer.java
 +++ b/src/main/java/net/minecraft/server/MinecraftServer.java
 @@ -296,7 +296,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
@@ -34,7 +34,7 @@ index d76dae9ce9022308b316080ac48b7030d674cc6b..e9d56d75b7c648f04d3a56942b286609
      public final double[] recentTps = new double[ 3 ];
      // Spigot end
      public final io.papermc.paper.configuration.PaperConfigurations paperConfigurations; // Paper - add paper configuration files
-@@ -1020,6 +1021,57 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+@@ -1019,6 +1020,57 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
      {
          return ( avg * exp ) + ( tps * ( 1 - exp ) );
      }
@@ -92,7 +92,7 @@ index d76dae9ce9022308b316080ac48b7030d674cc6b..e9d56d75b7c648f04d3a56942b286609
      // Spigot End
  
      protected void runServer() {
-@@ -1034,7 +1086,10 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+@@ -1033,7 +1085,10 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
  
              // Spigot start
              Arrays.fill( this.recentTps, 20 );
@@ -104,10 +104,10 @@ index d76dae9ce9022308b316080ac48b7030d674cc6b..e9d56d75b7c648f04d3a56942b286609
              while (this.running) {
                  long i;
  
-@@ -1057,15 +1112,22 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+@@ -1055,15 +1110,22 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+                     }
                  }
                  // Spigot start
-                 ++MinecraftServer.currentTickLong; // Paper - track current tick as a long
 -                if ( tickCount++ % MinecraftServer.SAMPLE_INTERVAL == 0 )
 -                {
 -                    long curTime = Util.getMillis();
@@ -135,7 +135,7 @@ index d76dae9ce9022308b316080ac48b7030d674cc6b..e9d56d75b7c648f04d3a56942b286609
                  // Spigot end
  
                  boolean flag = i == 0L;
-@@ -1075,7 +1137,8 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+@@ -1073,7 +1135,8 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
                      this.debugCommandProfiler = new MinecraftServer.TimeProfiler(Util.getNanos(), this.tickCount);
                  }