Fixed NPE in ServerConfigurationManager when sometimes attempting to flee the End

src/main/java/net/minecraft/server/ServerConfigurationManager.java

@@ -321,9 +321,11 @@ public class ServerConfigurationManager {
                 toLocation = toWorld == null ? null : new Location(toWorld.getWorld(), (entityplayer.locX * blockRatio), entityplayer.locY, (entityplayer.locZ * blockRatio), entityplayer.yaw, entityplayer.pitch);
             } else {
                 ChunkCoordinates coords = toWorld.d();
+                if (coords != null) {
                     toLocation = new Location(toWorld.getWorld(), coords.x, coords.y, coords.z, 90, 0);
                 }
             }
+        }
 
         org.bukkit.craftbukkit.PortalTravelAgent pta = new org.bukkit.craftbukkit.PortalTravelAgent();
         PlayerPortalEvent event = new PlayerPortalEvent((Player) entityplayer.getBukkitEntity(), fromLocation, toLocation, pta);