#1277: Add keepSpawnInMemory setting to WorldCreator

By: Jishuna <joshl5324@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -1137,6 +1137,7 @@ public final class CraftServer implements Server {
 
         WorldServer internal = (WorldServer) new WorldServer(console, console.executor, worldSession, worlddata, worldKey, worlddimension, getServer().progressListenerFactory.create(11),
                 worlddata.isDebugWorld(), j, creator.environment() == Environment.NORMAL ? list : ImmutableList.of(), true, console.overworld().getRandomSequences(), creator.environment(), generator, biomeProvider);
+        internal.keepSpawnInMemory = creator.keepSpawnInMemory();
 
         if (!(worlds.containsKey(name.toLowerCase(java.util.Locale.ENGLISH)))) {
             return null;