[quant][graphmode][fx] Add support for one value being quantized with different qconfigs (#53586)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53586
Previously one value can only be quantized to one dtype, this PR adds the support for quantizing one value
in the fx graph with multiple dtypes, e.g. first quantize to int8 and then float16
might do some followup PRs to clean up the hacks and refactor the code.
Test Plan:
python test/test_quantization.py TestQuantizeFx.test_multiple_qconfigs_single_value
Imported from OSS
Reviewed By: vkuzo
Differential Revision: D26912676
fbshipit-source-id: ae3653fd67f05870a3a9e808f491871826c555d5
