Fix minor windows compilation change

mln/core/image/ndimage.hpp

@@ -774,7 +774,7 @@ namespace mln
         q.rem += static_cast<int>(m_index_strides[i]);
         q.quot -= 1;
       }
-      p[i] += q.quot;
+      p[i] += static_cast<short>(q.quot);
       diff = q.rem;
     }
 

tests/core/image/image_ops.cpp

@@ -99,8 +99,6 @@ TEST(Core, Image2d_WhereOperator)
   auto f4 = where(x > 12, (uint8)0, (uint8)1); // RValue image + Scalar + Scalar
 
   ASSERT_TRUE(all(f1 >= 12));
-  // MSVC : uint8&, clang/gcc : const uint8&
-  ASSERT_TRUE((std::is_same<mln_reference(decltype(f1)), const uint8&>() ||
-               std::is_same<mln_reference(decltype(f1)), uint8&>()));
+  ASSERT_TRUE((std::is_same<mln_reference(decltype(f1)), const uint8&>()));
   ASSERT_TRUE((std::is_same<mln_reference(decltype(f2)), uint8&>()));
 }