message: make TFLite kernel tests work again
  pow_test.cc doesn't build with
  ```
  bazel test -c opt //tensorflow/contrib/lite/kernels:all
  ```
  s/int32/int32_t/ to make it build and run
diff: @@ -50,22 +50,22 @@ class PowOpModel : public SingleOpModel {
  };
  TEST(PowOpModel, Simple) {
  - PowOpModel<int32> model({TensorType_INT32, {1, 2, 2, 1}},
  + PowOpModel<int32_t> model({TensorType_INT32, {1, 2, 2, 1}},
  {TensorType_INT32, {1, 2, 2, 1}},
  {TensorType_INT32, {}});
  - model.PopulateTensor<int32>(model.input1(), {12, 2, 7, 8});
  - model.PopulateTensor<int32>(model.input2(), {1, 2, 3, 1});
  + model.PopulateTensor<int32_t>(model.input1(), {12, 2, 7, 8});
  + model.PopulateTensor<int32_t>(model.input2(), {1, 2, 3, 1});
  model.Invoke();
  EXPECT_THAT(model.GetOutputShape(), ElementsAre(1, 2, 2, 1));
  EXPECT_THAT(model.GetOutput(), ElementsAre(12, 4, 343, 8));
  }
  TEST(PowOpModel, NegativeAndZeroValue) {
  - PowOpModel<int32> model({TensorType_INT32, {1, 2, 2, 1}},
  + PowOpModel<int32_t> model({TensorType_INT32, {1, 2, 2, 1}},
  {TensorType_INT32, {1, 2, 2, 1}},
  {TensorType_INT32, {}});
  - model.PopulateTensor<int32>(model.input1(), {0, 2, -7, 8});
  - model.PopulateTensor<int32>(model.input2(), {1, 2, 3, 0});
  + model.PopulateTensor<int32_t>(model.input1(), {0, 2, -7, 8});
  + model.PopulateTensor<int32_t>(model.input2(), {1, 2, 3, 0});
  model.Invoke();
  EXPECT_THAT(model.GetOutputShape(), ElementsAre(1, 2, 2, 1));
  EXPECT_THAT(model.GetOutput(), ElementsAre(0, 4, -343, 1));
  @@ -98,10 +98,10 @@ TEST(PowOpModel, NegativeFloatTest) {
  }
  TEST(PowOpModel, BroadcastTest) {
  - PowOpModel<int32> model({TensorType_INT32, {1, 2, 2, 1}},
  + PowOpModel<int32_t> model({TensorType_INT32, {1, 2, 2, 1}},
  {TensorType_INT32, {1}}, {TensorType_INT32, {}});
  - model.PopulateTensor<int32>(model.input1(), {12, 2, 7, 8});
  - model.PopulateTensor<int32>(model.input2(), {4});
  + model.PopulateTensor<int32_t>(model.input1(), {12, 2, 7, 8});
  + model.PopulateTensor<int32_t>(model.input2(), {4});
  model.Invoke();
  EXPECT_THAT(model.GetOutputShape(), ElementsAre(1, 2, 2, 1));
  EXPECT_THAT(model.GetOutput(), ElementsAre(20736, 16, 2401, 4096));
  