Do not use deprecated functions

[naoyam]

c10::variant causes lots of compiler warnings like:

../c10/util/variant.h:2256:9: warning: definition of implicit copy constructor for 'impl<double, long>' is deprecated because it has a user-declared copy assignment operator [-Wdeprecated-copy]
  impl& operator=(const impl& other) = default;
        ^
../c10/util/variant.h:2394:3: note: in implicit copy constructor for 'c10::detail_::impl<double, long>' first required here
  variant(variant&&) = default;
  ^
../torch/csrc/jit/codegen/cuda/dynamic_type.h:14:25: note: in defaulted move constructor for 'c10::variant<double, long>' first required here
class TORCH_CUDA_CU_API IntOrDouble {
                        ^
../torch/csrc/jit/codegen/cuda/dynamic_type.h:59:3: note: in implicit move constructor for 'torch::jit::fuser::cuda::IntOrDouble' first required here
  DEFINE_ARITHMETIC_OP(+)
  ^
../torch/csrc/jit/codegen/cuda/dynamic_type.h:41:16: note: expanded from macro 'DEFINE_ARITHMETIC_OP'
        return IntOrDouble(as<double>() op other.as<double>());   \

Similar warnings are dumped for other uses of the class, but this PR at least avoids them for IntOrDouble

I'm using clang 13. Would be happy to know if there's better workarounds.

[csarofeen]

Seems fine.

[zasdfgbnm]

Looks like this is an issue of c10:: variant, because according to https://en.cppreference.com/w/cpp/utility/variant/variant, the copy constructor should not be deprecated. But fine, these compiler warnings are super annoying, and whatever way to get rid of this warning is good.

[naoyam]

yeah, it's not your fault. I see many other same warnings, which are really annoying.