Fix WeakIValueEq (#21891)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21891
ghimport-source-id: a037850c96fe803540412db9a88548fa41f2d4f0
Test Plan: Imported from OSS
Differential Revision: D15871588
Pulled By: jamesr66a
fbshipit-source-id: ecfdece1285c0737d0b1dc2afe959c43d9413001
