remove linkWorldPoses cache (no longer needed)

Signed-off-by: Ashton Larkin <[email protected]>

src/systems/physics/Physics.cc

@@ -218,11 +218,6 @@ class ignition::gazebo::systems::PhysicsPrivate
   /// \brief Keep track of what entities are static (models and links).
   public: std::unordered_set<Entity> staticEntities;
 
-  /// \brief Keep track of poses for links attached to non-static models.
-  /// This allows for skipping pose updates if a link's pose didn't change
-  /// after a physics step.
-  public: std::unordered_map<Entity, ignition::math::Pose3d> linkWorldPoses;
-
   /// \brief A map between model entity ids in the ECM to whether its battery
   /// has drained.
   public: std::unordered_map<Entity, bool> entityOffMap;
@@ -1151,7 +1146,6 @@ void PhysicsPrivate::RemovePhysicsEntities(const EntityComponentManager &_ecm)
             this->entityLinkMap.Remove(childLink);
             this->topLevelModelMap.erase(childLink);
             this->staticEntities.erase(childLink);
-            this->linkWorldPoses.erase(childLink);
           }
 
           for (const auto &childJoint :