Revert D25003113: make validate debug-only in Device copy ctr
Test Plan: revert-hammer
Differential Revision:
D25003113 (https://github.com/pytorch/pytorch/commit/4b26cafb8fa7eef7cbfdc0327f85f30e0a38e8ec)
Original commit changeset: e17e6495db65
fbshipit-source-id: fd636c954a97bd80892464feb974a11b9dd96899
