Revert "Revert "Implement sym_sizes to create proper IR for sym ints representing tensor sizes (#76836)""
This reverts commit c35bd8d423ca53408c3aa39c2280167f3a22cea0.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/77719
Approved by: https://github.com/Chillee, https://github.com/malfet
