Remove patch that was made obsolete by vanilla (#8847)

patches/server/0581-Add-Block-isValidTool.patch

@@ -1,20 +0,0 @@
-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 30b5a78a93405f3a03624ed1331670770aaa3765..974ab329f92f488aba0999cef25e3b8e7e062209 100644
---- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
-+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
-@@ -743,5 +743,9 @@ public class CraftBlock implements Block {
-         }
-         return speed;
-     }
-+
-+    public boolean isValidTool(ItemStack itemStack) {
-+        return getDrops(itemStack).size() != 0;
-+    }
-     // Paper end
- }