[AT-VK][EZ] Define OpNode constructor (#120362)
Instead of using `emplace_back()`. This will be useful throughout the rest of the stack.
Differential Revision: [D53982443](https://our.internmc.facebook.com/intern/diff/D53982443/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120362
Approved by: https://github.com/SS-JIA
