[quant][fx] Remove is_output_quantized from QuantizeHandler (#74843)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74843
is_output_quantized is used to check if we should quantize the op based on the dtype configuration in qconfig and what
is supported by the backend, we'll skip inserting observer if the dtype configuration is not supported by the backend,
this is now supported by backend_config_dict, and we can remove this function now.
Also we previously supported fp16 static quantization for some ops for one of our internal use case, and now it is not required, so
we can remove them
Test Plan:
python test/test_quantization.py TestQuantizeFx
python test/test_quantization.py TestQuantizeFxOps
Imported from OSS
Reviewed By: andrewor14
Differential Revision: D35190541
fbshipit-source-id: 623d961810737ec01e1f8b269ec48a6a99bb284a
(cherry picked from commit a405998c60c0146dbd5feef60e2d5cb3b0aa289c)
