message: dnn(ocl): fix wrong usage of stalled .getMat() pointers
  Temporary object lifetime must be greater than pointer usage.
diff: @@ -1230,20 +1230,22 @@ bool OCL4DNNConvSpatial<float>::verifyResult(const UMat &bottom,
  tuned_ = saved_tuned;
  UMat new_top, new_verify_top;
  - float *data, *verify_data;
  + Mat mat_top, mat_verify_top;
  if (use_half_)
  {
  convertFp16(top, new_top);
  convertFp16(verifyTop, new_verify_top);
  - data = (float *)new_top.getMat(ACCESS_READ).ptr<float>();
  - verify_data = (float *)new_verify_top.getMat(ACCESS_READ).ptr<float>();
  + mat_top = new_top.getMat(ACCESS_READ);
  + mat_verify_top = new_verify_top.getMat(ACCESS_READ);
  }
  else
  {
  - data = (float *)top.getMat(ACCESS_READ).ptr<float>();
  - verify_data = (float *)verifyTop.getMat(ACCESS_READ).ptr<float>();
  + mat_top = top.getMat(ACCESS_READ);
  + mat_verify_top = verifyTop.getMat(ACCESS_READ);
  }
  + const float* data = mat_top.ptr<float>();
  + const float* verify_data = mat_verify_top.ptr<float>();
  for (int32_t n = 0; n < num_; ++n) {
  for (int32_t g = 0; g < group_; ++g) {
  