[NNC] Fix crash when simplifying certain subtractions (#46108)
Summary:
Fixes a crash bug in the IRSimplifier when the LHS is a Term (e.g. 2x) and the RHS is a Polynomial (e.g. 2x+1).
This case crashes 100% of the time so I guess it's not very common in models we've been benchmarking.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46108
Reviewed By: agolynski
Differential Revision: D24226593
Pulled By: nickgg
fbshipit-source-id: ef454c855ff472febaeba16ec34891df932723c0
