Handle Scalars Better (#17875)
Summary:
This PR allows Scalars to be castable with `int()` and `float()`, allows scalars to match with float arguments, and prints out a better error message if `x.item()` is used as an int.
Scalars are a very uncommon case, and I don't think we want to add the maintenance burden of building out op coverage for it. It's more maintainable to better handle converting it to int/float.
Fix https://github.com/pytorch/pytorch/issues/17652
Also note: https://github.com/pytorch/pytorch/issues/16849
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17875
Differential Revision: D14411138
Pulled By: eellison
fbshipit-source-id: a4e957cefb0ffd10ddb234d92f6d1558cfce8751
