Player: Ensure we always get flagged as closed when parent constructor was never called

This was causing unexpected bugs when players got disconnected during the login sequence.

src/pocketmine/Player.php

@@ -2990,6 +2990,8 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 
 				if($this->constructed){
 					parent::close();
+				}else{
+					$this->closed = true;
 				}
 				$this->spawned = false;