Don't use implementation details for old sorters

We are removing old sorters, partitally because it is assumed that users
can reimplement them with simple compositions of existing components.
Using implementation details to reimplement them defeats the point.

Author: Morwenn

tests/testing-tools/old_sorters.h

@@ -45,10 +45,8 @@ struct old_default_sorter:
     >
 {};
 
-namespace cppsort
-{
     template<>
-    struct stable_adapter<::old_default_sorter>:
+    struct cppsort::stable_adapter<::old_default_sorter>:
         cppsort::merge_sorter
     {
         stable_adapter() = default;
@@ -57,7 +55,6 @@ namespace cppsort
             stable_adapter()
         {}
     };
-}
 
 ////////////////////////////////////////////////////////////
 // drop_merge_sorter
@@ -94,34 +91,29 @@ struct old_verge_sorter:
     old_verge_sorter() = default;
 };
 
-namespace cppsort
-{
     template<>
-    struct stable_adapter<::old_verge_sorter>:
-        cppsort::sorter_facade<
-            cppsort::detail::verge_adapter_impl<
+    struct cppsort::stable_adapter<::old_verge_sorter>:
+        cppsort::stable_t<
+            cppsort::verge_adapter<
                 cppsort::hybrid_adapter<
                     cppsort::pdq_sorter,
                     cppsort::quick_merge_sorter
-                >,
-                true
+                >
             >
         >
     {
         stable_adapter() = default;
 
         constexpr explicit stable_adapter(const ::old_verge_sorter&):
-            cppsort::sorter_facade<
-                cppsort::detail::verge_adapter_impl<
+            cppsort::stable_t<
+                cppsort::verge_adapter<
                     cppsort::hybrid_adapter<
                         cppsort::pdq_sorter,
                         cppsort::quick_merge_sorter
-                    >,
-                    true
+                    >
                 >
             >()
         {}
     };
-}
 
 #endif // CPPSORT_TESTSUITE_OLD_SORTERS_H_