[caffe2] Allow memonger to optimize nets with inplace(enforced) ops (#46560)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46560
Follow-up for D24236604 (https://github.com/pytorch/pytorch/commit/16c52d918b8b3e90c81eb6d2a1fb0945dc187932).
For nets that pass the schema check, memonger actually makes sure to preserve the inplaceness of operators if they are already inplace. So we can safely enable it for correct input nets.
(Note: this ignores all push blocking failures!)
Differential Revision: D24402482
fbshipit-source-id: a7e95cb0e3eb87adeac79b9b69eef207957b0bd5
