[quant][graph] Add _choose_qparams function for graph mode (#35235)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35235
For dynamic quantization in graph mode, we need an operator that returns the qparams of the tensor
similar to the linear_dynamic quantized op
Test Plan:
python test/test_quantized_tensor.py TestQuantizedTensor.test_choose_qparams
Imported from OSS
Differential Revision: D20608793
fbshipit-source-id: b923b2620421b32d05f4097db0d6153d53198221