[SPIGOT-946] Begin making use of access transforms to simplify patching.

nms-patches/EntityPotion.patch

@@ -1,6 +1,6 @@
 --- a/net/minecraft/server/EntityPotion.java
 +++ b/net/minecraft/server/EntityPotion.java
-@@ -3,9 +3,16 @@
+@@ -3,6 +3,13 @@
  import java.util.Iterator;
  import java.util.List;
  
@@ -13,11 +13,7 @@
 +
  public class EntityPotion extends EntityProjectile {
  
--    private ItemStack item;
-+    public ItemStack item; // CraftBukkit - public
- 
-     public EntityPotion(World world) {
-         super(world);
+     public ItemStack item;
 @@ -57,13 +64,16 @@
          if (!this.world.isClientSide) {
              List list = Items.POTION.h(this.item);