fx quant: clean up names of quantize handlers (#53614)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53614
Ensures that every subclass of `QuantizeHandler` has a clear name. This
prevents ambiguous names like `Cat`, which look like a module but are
really a quantize handler.
Test Plan:
```
python test/test_quantization.py TestQuantizeFx
```
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D26914784
fbshipit-source-id: 6dca7e27975c09f422f8e36f1d2b709bf3eaaadf
