ns for fx: add test for op relationship coverage (#55837)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55837
Adds a test that checks that all of the relevant op pairs defined in
`quantization_mappings.py` are also defined as related by Numerical
Suite.
Note: this does not cover all the ops, just the ones in
`quantization_mappings.py`. A future PR will fill out the remainder.
Test Plan:
```
python test/test_quantization.py TestFXGraphMatcher.test_op_relationship_mapping
```
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D27719979
fbshipit-source-id: 9e852ef94da5f7a653ea15ba52c68a89c8e30208
