[jit] Fix aug assign for non-tensor attributes (#32993)
Summary:
Instead of erroring out this de-sugars augmented assignments to class
members from `self.a += 1` to `self.a = self.a + 1`.
Fixes #32973
](https://our.intern.facebook.com/intern/diff/19737636/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32993
Pulled By: driazati
Differential Revision: D19737636
fbshipit-source-id: 07307cde88d8c348a7affdafe26db21c74e28ec0
