Performance patches prerequisite (#2802)

Prereq changes for the coming storm of performance patches.
Includes optimising incremental saving

Spigot-Server-Patches/Speedup-BlockPos-by-fixing-inlining.patch

@@ -21,7 +21,7 @@ This is based upon conclusions drawn from inspecting the assenmbly generated byt
 They had 'callq' (invoke) instead of 'mov' (get from memory) instructions.
 
 diff --git a/src/main/java/net/minecraft/server/BaseBlockPosition.java b/src/main/java/net/minecraft/server/BaseBlockPosition.java
-index 71089442c..c439a8d01 100644
+index 71089442c1..c439a8d019 100644
 --- a/src/main/java/net/minecraft/server/BaseBlockPosition.java
 +++ b/src/main/java/net/minecraft/server/BaseBlockPosition.java
 @@ -0,0 +0,0 @@ import javax.annotation.concurrent.Immutable;
@@ -110,7 +110,7 @@ index 71089442c..c439a8d01 100644
          return (int) (f + f1 + f2);
      }
 diff --git a/src/main/java/net/minecraft/server/BlockPosition.java b/src/main/java/net/minecraft/server/BlockPosition.java
-index 1cdf0346f..5a505b753 100644
+index 5dbd3e60fe..e9ea232a78 100644
 --- a/src/main/java/net/minecraft/server/BlockPosition.java
 +++ b/src/main/java/net/minecraft/server/BlockPosition.java
 @@ -0,0 +0,0 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
@@ -189,16 +189,19 @@ index 1cdf0346f..5a505b753 100644
 +            return this.d(this.x + i, this.y + j, this.z + k);
          }
  
+         public final void setX(final int x) { this.o(x); } // Paper - OBFHELPER
          public void o(int i) {
 -            this.b = i;
 +            this.x = i; // Paper change to x
          }
  
+         public final void setY(final int y) { this.p(y); } // Paper - OBFHELPER
          public void p(int i) {
 -            this.c = i;
 +            this.y = i; // Paper change to y
          }
  
+         public final void setZ(final int z) { this.q(z); } // Paper - OBFHELPER
          public void q(int i) {
 -            this.d = i;
 +            this.z = i; // Paper change to z