AK: Simplify HashTable::remove_all_matching()

Just walk the table from start to finish, deleting buckets as we go.
This removes the need for remove() to return an iterator, which is
preventing me from implementing hash table auto-shrinking.

AK/HashMap.h

@@ -79,16 +79,9 @@ public:
     template<typename TUnaryPredicate>
     bool remove_all_matching(TUnaryPredicate predicate)
     {
-        bool something_was_removed = false;
-        for (auto it = begin(); it != end();) {
-            if (predicate(it->key, it->value)) {
-                it = remove(it);
-                something_was_removed = true;
-            } else {
-                ++it;
-            }
-        }
-        return something_was_removed;
+        return m_table.template remove_all_matching([&](auto& entry) {
+            return predicate(entry.key, entry.value);
+        });
     }
 
     using HashTableType = HashTable<Entry, EntryTraits, IsOrdered>;