cleanups to alias analysis interfaces (#21397)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21397
ghimport-source-id: 8733e1af2fe66a3f4494a2c24c82a039375a982e
Reviewed By: jamesr66a
Differential Revision: D15642662
Pulled By: suo
fbshipit-source-id: ae66b7b4f19f255d6fe0e7e804bd0df6d86cb8d1
