Fix issues with new ChunkGenerator API

- RegionAccessor#setType / RegionAccessor#setBlockData doesn't run entity removal logic
- RegionAccessor#generateTree crashes by bee nest (TreeType#TALL_BIRCH)

By: DerFrZocker <derrieple@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java

@@ -41,6 +41,10 @@ public class CraftBlockEntityState<T extends TileEntity> extends CraftBlockState
         this.load(snapshot);
     }
 
+    public void refreshSnapshot() {
+        this.load(tileEntity);
+    }
+
     private T createSnapshot(T tileEntity) {
         if (tileEntity == null) {
             return null;

paper-server/src/main/java/org/bukkit/craftbukkit/block/CraftBlockState.java

@@ -34,12 +34,7 @@ public class CraftBlockState implements BlockState {
         this.data = ((CraftBlock) block).getNMS();
         this.flag = 3;
 
-        GeneratorAccess generatorAccess = ((CraftBlock) block).getHandle();
-        if (generatorAccess instanceof net.minecraft.world.level.World) {
-            this.weakWorld = null;
-        } else {
-            this.weakWorld = new WeakReference<>(generatorAccess);
-        }
+        setWorldHandle(((CraftBlock) block).getHandle());
     }
 
     public CraftBlockState(final Block block, int flag) {
@@ -62,6 +57,14 @@ public class CraftBlockState implements BlockState {
         return new CraftBlockState(CraftBlock.at(world, pos), flag);
     }
 
+    public void setWorldHandle(GeneratorAccess generatorAccess) {
+        if (generatorAccess instanceof net.minecraft.world.level.World) {
+            this.weakWorld = null;
+        } else {
+            this.weakWorld = new WeakReference<>(generatorAccess);
+        }
+    }
+
     public GeneratorAccess getWorldHandle() {
         if (weakWorld == null) {
             return world.getHandle();