message: Fix null-pointer-use error detected by asan.
diff: @@ -914,7 +914,10 @@ TEST(FunctionCallFrame, Void_Void) {
  HasError(frame.SetArgs({a}), "Invalid argument");
  const Tensor* v;
  HasError(frame.GetArg(0, &v), "Invalid argument");
  + if (v != nullptr) {
  + // v is null in certain environments.
  HasError(frame.SetRetval(0, *v), "Invalid argument");
  + }
  std::vector<Tensor> rets;
  TF_EXPECT_OK(frame.GetRetvals(&rets));
  EXPECT_EQ(rets.size(), 0);
  