remove the first world.flush_entities() in despawn

Author: jrobsonchase

crates/bevy_ecs/src/observer/mod.rs

@@ -1176,6 +1176,7 @@ mod tests {
 
         let ent = world.spawn(A).id();
 
+        let foo = world.entities().reserve_entity();
         // Despawn our entity, which runs the OnRemove observer and allocates a
         // new Entity.
         // Should not panic - if it does, then Entities was not flushed properly

crates/bevy_ecs/src/world/entity_ref.rs

@@ -1297,7 +1297,6 @@ impl<'w> EntityWorldMut<'w> {
     /// See [`World::despawn`] for more details.
     pub fn despawn(self) {
         let world = self.world;
-        world.flush_entities();
         let archetype = &world.archetypes[self.location.archetype_id];
 
         // SAFETY: Archetype cannot be mutably aliased by DeferredWorld