Fix dummy air blocks not being marked as air (#9440)

src/main/java/net/minecraftforge/registries/GameData.java

@@ -489,9 +489,10 @@ public class GameData
         }
 
         @Override
+        @Deprecated(forRemoval = true, since = "1.19.4")
         public Block createDummy(ResourceLocation key)
         {
-            Block ret = new BlockDummyAir(Block.Properties.of(Material.AIR));
+            Block ret = new DummyAirBlock(Block.Properties.of(Material.AIR).noCollission().noLootTable().air());
             return ret;
         }
 
@@ -514,9 +515,10 @@ public class GameData
             DebugLevelSource.initValidStates();
         }
 
-        private static class BlockDummyAir extends AirBlock //A named class so DummyBlockReplacementTest can detect if its a dummy
+        @Deprecated(forRemoval = true, since = "1.19.4")
+        private static class DummyAirBlock extends AirBlock
         {
-            private BlockDummyAir(Block.Properties properties)
+            private DummyAirBlock(Block.Properties properties)
             {
                 super(properties);
             }