ns for fx: qat test cases for unshadowed activations (#55508)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55508
Adds QAT test cases for unshadowed activation APIs.
Test Plan:
```
python test/test_quantization.py TestFXNumericSuiteCoreAPIs
```
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D27650406
fbshipit-source-id: bcbbdf1d32b8f8627c30d6aaf22607f34d1e2e08
