implemented quantize_per_tensor_dynamic and added a corresponding test script (#68004)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/68004
Test Plan: Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D32301792
Pulled By: dzdang
fbshipit-source-id: f680557ba4736d095efc33e8c92111265f25aee0
