[quant][graphmode][fx][refactor] is_output_quantized (#47879)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/47879
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D24928796
fbshipit-source-id: 55c49243b6a0b4811953cf72af57e5f56be8c419
