[XLA:GPU] Make VLOG explanation in SortRewriter more helpful.

Add the dtypes for which a CUB kernel is unavailable to the log output.

PiperOrigin-RevId: 703067645

third_party/xla/xla/service/gpu/transforms/sort_rewriter.cc

@@ -436,7 +436,11 @@ bool IsCubCompatibleSort(const HloSortInstruction* sort_op) {
     return false;
   }
   if (!CreateRunner(*sort_analysis).ok()) {
-    VLOG(2) << "Unsupported operand types (no compiled CUB kernels)";
+    VLOG(2) << "Unsupported operand types (no compiled CUB kernels): "
+            << PrimitiveType_Name(sort_analysis->key_type) << " "
+            << (sort_analysis->value_type.has_value()
+                    ? PrimitiveType_Name(sort_analysis->value_type.value())
+                    : "");
     return false;
   }
   VLOG(2) << "Sort operation is compatible";