C++17 friendly iterator implementation

Get rid of std::iterator inheritence for `c10::DictIterator`, `c10::IListRefIterator` and `c10::ListIterator`

Followup after #90174

Fixes deprecation warning and extension compilation failures using VC++
that raises following errors:
```
C:\actions-runner\_work\pytorch\pytorch\build\win_tmp\build\torch\include\ATen/core/IListRef.h(517): error C4996: 'std::iterator<std::bidirectional_iterator_tag,T,ptrdiff_t,T *,T &>::value_type': warning STL4015: The std::iterator class template (used as a base class to provide typedefs) is deprecated in C++17. (The <iterator> header is NOT deprecated.) The C++ Standard has never required user-defined iterators to derive from std::iterator. To fix this warning, stop deriving from std::iterator and start providing publicly accessible typedefs named iterator_category, value_type, difference_type, pointer, and reference. Note that value_type is required to be non-const, even for constant iterators. You can define _SILENCE_CXX17_ITERATOR_BASE_CLASS_DEPRECATION_WARNING or _SILENCE_ALL_CXX17_DEPRECATION_WARNINGS to acknowledge that you have received this warning.

C:\actions-runner\_work\pytorch\pytorch\build\win_tmp\build\torch\include\ATen/core/List.h(169): error C4996: 'std::iterator<std::random_access_iterator_tag,T,ptrdiff_t,T *,T &>::difference_type': warning STL4015: The std::iterator class template (used as a base class to provide typedefs) is deprecated in C++17. (The <iterator> header is NOT deprecated.) The C++ Standard has never required user-defined iterators to derive from std::iterator. To fix this warning, stop deriving from std::iterator and start providing publicly accessible typedefs named iterator_category, value_type, difference_type, pointer, and reference. Note that value_type is required to be non-const, even for constant iterators. You can define _SILENCE_CXX17_ITERATOR_BASE_CLASS_DEPRECATION_WARNING or _SILENCE_ALL_CXX17_DEPRECATION_WARNINGS to acknowledge that you have received this warning.

```

aten/src/ATen/core/Dict.h

@@ -101,8 +101,15 @@ class DictEntryRef final {
 // this wraps map_type::iterator to make sure user code can't rely
 // on it being the type of the underlying map.
 template<class Key, class Value, class Iterator>
-class DictIterator final : public std::iterator<std::forward_iterator_tag, DictEntryRef<Key, Value, Iterator>> {
+class DictIterator final {
 public:
+   // C++17 friendly std::iterator implementation
+  using iterator_category = std::forward_iterator_tag;
+  using value_type = DictEntryRef<Key, Value, Iterator>;
+  using difference_type = std::ptrdiff_t;
+  using pointer = value_type*;
+  using reference = value_type&;
+
   explicit DictIterator() = default;
   ~DictIterator() = default;
 
@@ -136,7 +143,7 @@ class DictIterator final : public std::iterator<std::forward_iterator_tag, DictE
     return &entryRef_;
   }
 
-  friend typename std::iterator<std::random_access_iterator_tag, DictEntryRef<Key, Value, Iterator>>::difference_type operator-(const DictIterator& lhs, const DictIterator& rhs) {
+  friend difference_type operator-(const DictIterator& lhs, const DictIterator& rhs) {
     return lhs.entryRef_.iterator_ - rhs.entryRef_.iterator_;
   }
 

aten/src/ATen/core/IListRef.h

@@ -359,7 +359,7 @@ using MaterializedIListRef = std::vector<MaterializedIListRefElem<T>>;
  *     than 0.
  */
 template <typename T>
-class IListRefIterator : public std::iterator<std::bidirectional_iterator_tag, T> {
+class IListRefIterator {
  private:
 #define DEFINE_FRIEND_CLASS(TAG, ...)                        \
   friend class detail::IListRefTagImpl<IListRefTag::TAG, T>; \
@@ -371,6 +371,13 @@ class IListRefIterator : public std::iterator<std::bidirectional_iterator_tag, T
 #undef DEFINE_FRIEND_CLASS
 
  public:
+  // C++17 friendly std::iterator implementation
+  using iterator_category = std::bidirectional_iterator_tag;
+  using value_type = T;
+  using difference_type = std::ptrdiff_t;
+  using pointer = T*;
+  using reference = T&;
+
   using unboxed_iterator_type = typename detail::
       IListRefTagImpl<IListRefTag::Unboxed, T>::list_type::const_iterator;
   using boxed_iterator_type = typename detail::

aten/src/ATen/core/List.h

@@ -111,13 +111,15 @@ class ListElementReference final {
 // this wraps vector::iterator to make sure user code can't rely
 // on it being the type of the underlying vector.
 template <class T, class Iterator>
-class ListIterator final : public std::iterator<
-                               std::random_access_iterator_tag,
-                               T,
-                               std::ptrdiff_t,
-                               T*,
-                               ListElementReference<T, Iterator>> {
+class ListIterator final {
  public:
+   // C++17 friendly std::iterator implementation
+  using iterator_category = std::random_access_iterator_tag;
+  using value_type = T;
+  using difference_type = std::ptrdiff_t;
+  using pointer = T*;
+  using reference = ListElementReference<T, Iterator>;
+
   explicit ListIterator() = default;
   ~ListIterator() = default;
 
@@ -166,7 +168,7 @@ class ListIterator final : public std::iterator<
     return ListIterator{iterator_ - offset};
   }
 
-  friend typename std::iterator<std::random_access_iterator_tag, T>::difference_type operator-(const ListIterator& lhs, const ListIterator& rhs) {
+  friend difference_type operator-(const ListIterator& lhs, const ListIterator& rhs) {
     return lhs.iterator_ - rhs.iterator_;
   }