AK: Add take_first to HashTable and rename pop to take_last

This naming scheme matches Vector.

This also changes `take_last` to move the value it takes, and delete by
known pointer, avoiding a full lookup and potential copies.

AK/HashTable.h

@@ -405,12 +405,21 @@ public:
         return has_removed_anything;
     }
 
-    T pop()
+    T take_last()
     requires(IsOrdered)
     {
         VERIFY(!is_empty());
-        T element = *m_collection_data.tail->slot();
+        T element = move(*m_collection_data.tail->slot());
-        remove(element);
+        delete_bucket(*m_collection_data.tail);
+        return element;
+    }
+
+    T take_first()
+    requires(IsOrdered)
+    {
+        VERIFY(!is_empty());
+        T element = move(*m_collection_data.head->slot());
+        delete_bucket(*m_collection_data.head);
         return element;
     }
 

Tests/AK/TestHashTable.cpp

@@ -358,16 +358,16 @@ TEST_CASE(ordered_deletion_and_reinsertion)
     EXPECT_EQ(it, table.end());
 }
 
-TEST_CASE(ordered_pop)
+TEST_CASE(ordered_take_last)
 {
     OrderedHashTable<int> table;
     table.set(1);
     table.set(2);
     table.set(3);
 
-    EXPECT_EQ(table.pop(), 3);
+    EXPECT_EQ(table.take_last(), 3);
-    EXPECT_EQ(table.pop(), 2);
+    EXPECT_EQ(table.take_last(), 2);
-    EXPECT_EQ(table.pop(), 1);
+    EXPECT_EQ(table.take_last(), 1);
     EXPECT(table.is_empty());
 }
 
@@ -382,3 +382,31 @@ TEST_CASE(ordered_iterator_removal)
     EXPECT_EQ(it, map.end());
     EXPECT_EQ(map.size(), 1u);
 }
+
+TEST_CASE(ordered_remove_from_head)
+{
+    OrderedHashTable<int> map;
+    map.set(1);
+    map.set(2);
+    map.set(3);
+    map.set(4);
+    map.set(5);
+    map.set(6);
+
+    EXPECT_EQ(map.size(), 6u);
+
+    auto it = map.begin();
+    map.remove(it);
+    it = map.begin();
+    map.remove(it);
+    it = map.begin();
+    map.remove(it);
+    it = map.begin();
+    map.remove(it);
+    it = map.begin();
+    map.remove(it);
+    it = map.begin();
+    map.remove(it);
+
+    EXPECT_EQ(map.size(), 0u);
+}

Userland/Utilities/tsort.cpp

@@ -76,7 +76,7 @@ static void prioritize_nodes(Node& start, NodeMap& node_map, NodeStack& stack, b
             node.status = NodeStatus::Prioritized;
             outln("{}", stack.take_last().name);
         } else {
-            auto next_ancestor_name = node.ancestors.pop();
+            auto next_ancestor_name = node.ancestors.take_last();
             auto& next_ancestor = node_map.get(next_ancestor_name).release_value();
             if (next_ancestor.status == NodeStatus::Seen)
                 // If the same node is seen multiple times, this represents a cycle in