[fx2trt] add converter for acc_ops.hardtanh (#68550)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68550
Missing ops in https://fburl.com/gsheet/q06f1vrc
Test Plan: unit tests
Reviewed By: wushirong
Differential Revision: D32500303
fbshipit-source-id: 9266210ae229263f6bb2a60486c279ceb766ffdf
