Back out "Revert D21171334: [pytorch][PR] Change StorageImpl to track byte count rather than element count" (#37893)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37893
Original commit changeset: 50746043acf3
Test Plan: sandcastle and ossci
Reviewed By: malfet, seemethere, ngimel
Differential Revision: D21416509
fbshipit-source-id: 735ec4e61f9d36d4537f52dd2dc6267751aeb94b
