Make moving FunctionSchema efficient (#19773)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19773
const members can't be moved, so whenever somebody moved a function schema, it was copied instead.
This diff fixes this.
Reviewed By: dzhulgakov
Differential Revision: D15090323
fbshipit-source-id: 123a1d6b96ac46cb237966c0b072edebcdafe54c
