[quant][graphmode][fx] Use the new convert function instead of the old one in quant-fx2trt tests (#67065)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67065
Switching to use _convert_fx_do_not_use in the tests
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D31849077
fbshipit-source-id: 3688fc09ac538b6abc16ce87c600b8ee04acfcd1
