Remove "Implement-Chunk-Priority-Urgency-System-for-Chunks" (Fixes #5980)

Mojang made some changes to priorities in 1.17 and it seems that these changes
conflict with the changes made in this patch, which in some cases appears to
cause excessive rescheduling of tasks.

This, however, is not confirmed as such but seems to be the behavior that we're
seeing to cause this issue, if mojang has adopted the changes we suggested,
then a good chunk of this patch may be unneeded, but, this needs a much better
look than I'm currently able to do

patches/server/0637-Add-Block-isValidTool.patch

@@ -0,0 +1,20 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <jake.m.potrebic@gmail.com>
+Date: Mon, 6 Jul 2020 12:44:31 -0700
+Subject: [PATCH] Add Block#isValidTool
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
+index ef3d93ba8b4149aa479abc6e9787a8746f60ce1d..0b909c0e2137250895b17a0fb5da0c188c402fe1 100644
+--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
++++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
+@@ -819,5 +819,9 @@ public class CraftBlock implements Block {
+         }
+         return speed;
+     }
++
++    public boolean isValidTool(ItemStack itemStack) {
++        return getDrops(itemStack).size() != 0;
++    }
+     // Paper end
+ }