Update backward formula for torch.dot and add backward definition for torch.vdot (#45074)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45074
TODO: Add R -> C tests in https://github.com/pytorch/pytorch/pull/44744 (blocked on some JIT changes)
Test Plan: Imported from OSS
Reviewed By: gchanan
Differential Revision: D23975361
Pulled By: anjali411
fbshipit-source-id: 3512bd2962b588a198bc317673bd18cc96ac823f
