Remove optimization which gives worst benchmark results

Author: samueltardieu

src/directed/dijkstra.rs

@@ -213,17 +213,11 @@ where
     let mut target_reached = None;
     while let Some(SmallestHolder { cost, index }) = to_see.pop() {
         let successors = {
-            let (node, &(_, c)) = parents.get_index(index).unwrap();
+            let (node, _) = parents.get_index(index).unwrap();
             if stop(node) {
                 target_reached = Some(index);
                 break;
             }
-            // We may have inserted a node several time into the binary heap if we found
-            // a better way to access it. Ensure that we are currently dealing with the
-            // best path and discard the others.
-            if cost > c {
-                continue;
-            }
             successors(node)
         };
         for (successor, move_cost) in successors {