don't throw in constant prop (#25270)
Summary:
Don't throw in constant propagation, since the op we're running may not be reached. Previously we would only only catch `C10::Error`; however it's hard to maintain that the entire codebase doesn't throw any other types of errors, and some errors map nicely to python errors, like `std::index_error` to IndexError.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25270
Differential Revision: D17102545
Pulled By: eellison
fbshipit-source-id: 9fd485821743ad882e5c6fc912ca47b0b001b0e9
