axis bounds checking in split (#1178)

* Add kazum to contributers

* Add axis bounds checking in split

CONTRIBUTORS.md

@@ -63,3 +63,4 @@ List of Contributors
 - [Cody Hao Yu](https://github.com/comaniac)
 - [Chris Nuernberger](https://github.com/cnuernber)
 - [Tatsuya Nishiyama](https://github.com/nishi-t)
+- [Kazutaka Morita](https://github.com/kazum)

topi/include/topi/transform.h

@@ -310,6 +310,8 @@ inline Array<Tensor> split(const Tensor& x,
   if (axis < 0) {
     axis += static_cast<int>(x->shape.size());
   }
+  CHECK_LT(axis, x->shape.size()) << "axis out of bounds";
+
   auto src_axis_size = static_cast<int>(GetConstInt(x->shape[axis]));
 
   auto split_indices_val = GetConstIntValues(split_indices, "split_indices");