fixed the custom call site

Author: miladm

torch_xla/csrc/tensor_impl.cpp

@@ -123,7 +123,7 @@ at::IntArrayRef XLATensorImpl::sizes_custom() const {
 }
 
 c10::SymIntArrayRef XLATensorImpl::sym_sizes_custom() const {
-  auto sizes = sizes_default();
+  auto sizes = sizes_custom();
   return c10::SymIntArrayRef(reinterpret_cast<const c10::SymInt*>(sizes.data()),
                              sizes.size());
 }