pytorch

9d5607fc - [quant] Use PlaceholderObserver as default dynamic quant observer (#45343)

[quant] Use PlaceholderObserver as default dynamic quant observer (#45343) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/45343 Current default dynamic quant observer is not correct since we don't accumulate min/max and we don't need to calculate qparams. Test Plan: Imported from OSS Reviewed By: supriyar Differential Revision: D23933995 fbshipit-source-id: 3ff497c9f5f74c687e8e343ab9948d05ccbba09b