Revert D34111109: [FSDP] Implement apply()
Test Plan: revert-hammer
Differential Revision:
D34111109 (https://github.com/pytorch/pytorch/commit/1f29b3130af218847a043e58fdc64511bbe072fe)
Original commit changeset: 60d9d3f5c4d6
Original Phabricator Diff: D34111109 (https://github.com/pytorch/pytorch/commit/1f29b3130af218847a043e58fdc64511bbe072fe)
fbshipit-source-id: d959533f656a1fa69b2af7c029130f674fdd6023
(cherry picked from commit b0d3e2b1c368dea84b94cfa2a06c9e02c5a66906)
