Implement tensor.size(Dimname), tensor.stride(Dimname)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/22989
Test Plan: Imported from OSS
Differential Revision: D16364437
Pulled By: zou3519
fbshipit-source-id: 393a93fecac27b5d3b1a7f7692590d8fd5e95a5d
