Fix crash when deleting a collider.

src/geometry/contact_generator/heightfield_shape_contact_generator.rs

@@ -71,10 +71,10 @@ fn do_generate_contacts(
             } else {
                 manifold.subshape_index_pair.1
             };
-            println!(
-                "Restoring for {} [chosen with {:?}]",
-                subshape_id, manifold.subshape_index_pair
-            );
+            // println!(
+            //     "Restoring for {} [chosen with {:?}]",
+            //     subshape_id, manifold.subshape_index_pair
+            // );
 
             // Use dummy shapes for the dispatch.
             #[cfg(feature = "dim2")]

src/pipeline/physics_pipeline.rs

@@ -68,8 +68,8 @@ impl PhysicsPipeline {
         bodies: &mut RigidBodySet,
         colliders: &mut ColliderSet,
     ) {
-        // broad_phase.maintain(colliders);
-        // narrow_phase.maintain(colliders, bodies);
+        broad_phase.maintain(colliders);
+        narrow_phase.maintain(colliders, bodies);
     }
 
     /// Executes one timestep of the physics simulation.