ns for fx: skip operator.add and operator.mul when shadowing (#76504)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76504
Shadowing for add and mul is not implemented, this PR fixes the skipping
logic to also skip the `operator.add` and `operator.mul` flavor of these
operators.
Test Plan:
```
python test/test_quantization.py -k test_mul_add_skips_shadowing
```
Reviewed By: dzdang
Differential Revision: D35985997
Pulled By: vkuzo
fbshipit-source-id: f832e54a5461d3b182df4bb905357d6c66742e98
(cherry picked from commit 93ae9592f68873865ebfdc438bffb1c9486dd1c1)
