Use DefaultedList for equipment tracking

Because on 1.11+ a `null` item stack is not something that should exist.
This then also allows us to compare item stacks by value rather than only by
reference, potentially saving a few redundant entity equipment update
packets (but more importantly, also allows us to store a copy instead of the
original, which will be important for the next commit).

src/main/java/com/replaymod/core/versions/Patterns.java

@@ -15,6 +15,7 @@ import net.minecraft.client.render.Tessellator;
 import net.minecraft.client.render.entity.EntityRenderDispatcher;
 import net.minecraft.client.sound.PositionedSoundInstance;
 import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.item.ItemStack;
 import net.minecraft.resource.Resource;
 import net.minecraft.resource.ResourceManager;
 import net.minecraft.text.LiteralText;
@@ -49,6 +50,10 @@ import net.minecraft.client.util.Window;
 //$$ import net.minecraft.client.gui.GuiButton;
 //#endif
 
+//#if MC>=11100
+import net.minecraft.util.collection.DefaultedList;
+//#endif
+
 //#if MC>=10904
 import net.minecraft.sound.SoundEvent;
 import net.minecraft.util.crash.CrashCallable;
@@ -669,4 +674,13 @@ class Patterns {
         return manager.getResource(id);
         //#endif
     }
+
+    @Pattern
+    private static List<ItemStack> DefaultedList_ofSize_ItemStack_Empty(int size) {
+        //#if MC>=11100
+        return DefaultedList.ofSize(size, ItemStack.EMPTY);
+        //#else
+        //$$ return java.util.Arrays.asList(new ItemStack[size]);
+        //#endif
+    }
 }