ns for fx: extract common code in tests to util functions (#53748)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53748
Extracts common testing patterns for FX numeric suite into
util functions. No logic change.
Test Plan:
```
python test/test_quantization.py TestFXNumericSuiteCoreAPIs
python test/test_quantization.py TestFXNumericSuiteCoreAPIsModels
```
Imported from OSS
Reviewed By: raghuramank100
Differential Revision: D26967105
fbshipit-source-id: 9f6cbe75bb6d2ede142929e0c9e40812006c159d
