[quant][graph] Add useQuantizable function (#36691)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36691
Enables to selectively insert observers at the inputs of aten/call functionc
Test Plan:
test_quantize_script.py
Imported from OSS
Differential Revision: D21055597
fbshipit-source-id: b47733b94b127d7a47b3224da7af98f0da38d30d
