allowing stable sort by key to use radix sort

clang/runtime/dpct-rt/include/dpct/dpl_extras/algorithm.h

@@ -550,12 +550,9 @@ void stable_sort(Policy &&policy, Iter1 keys_first, Iter1 keys_last,
           std::is_same<typename std::iterator_traits<Iter2>::iterator_category,
                        std::random_access_iterator_tag>::value,
       "Iterators passed to algorithms must be random-access iterators.");
-  std::stable_sort(
-      std::forward<Policy>(policy),
-      oneapi::dpl::make_zip_iterator(keys_first, values_first),
-      oneapi::dpl::make_zip_iterator(
-          keys_last, values_first + std::distance(keys_first, keys_last)),
-      internal::compare_key_fun<Comp>(comp));
+  //oneDPL::sort_by_key is explicitly stable
+  oneapi::dpl::sort_by_key(std::forward<Policy>(policy), keys_first, keys_last,
+                           values_first, comp);
 }
 
 template <class Policy, class Iter1, class Iter2>