Add index number to THArgCheck error message (#38978)
Summary:
- Resolving the feature introduced in https://github.com/pytorch/pytorch/issues/38652
- Since the iteration will be terminated once the error occurred, perhaps we can only give the current index which caused the error.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38978
Differential Revision: D21722426
Pulled By: ezyang
fbshipit-source-id: edfc3f7a320584ba22d790f2b79c3726e99aae2a
