Revert D32606547: torch/monitor: add C++ events and handlers
Test Plan: revert-hammer
Differential Revision:
D32606547 (https://github.com/pytorch/pytorch/commit/e61fc1c03b64e61ca4f5bbe278db7ee2cf35e8ff)
Original commit changeset: a00d0364092d
Original Phabricator Diff: D32606547 (https://github.com/pytorch/pytorch/commit/e61fc1c03b64e61ca4f5bbe278db7ee2cf35e8ff)
fbshipit-source-id: fbaf2cc06ad4bec606e8a9c6f591d65c04e6fa56
