Fix tests requiring MultiThreaded executor

Author: A-Walrus

crates/bevy_ecs/src/query/mod.rs

@@ -791,7 +791,7 @@ mod tests {
             }
         }
 
-        let mut schedule = Schedule::single_threaded();
+        let mut schedule = Schedule::default(); // Uses MultiThreaded executor
         schedule.add_systems((propagate_system, modify_system).chain());
         schedule.run(&mut world);
         world.clear_trackers();

crates/bevy_ecs/src/schedule/mod.rs

@@ -103,7 +103,7 @@ mod tests {
             use std::sync::{Arc, Barrier};
 
             let mut world = World::default();
-            let mut schedule = Schedule::single_threaded();
+            let mut schedule = Schedule::default(); // Uses MultiThreaded executor
             let thread_count = ComputeTaskPool::init(TaskPool::default).thread_num();
 
             let barrier = Arc::new(Barrier::new(thread_count));