[quant][eagermode][qat][test] Add numerical test for qat convert (#47376)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47376
For sigmoid, hardsimoid, tanh, leaky_relu
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D24734754
fbshipit-source-id: f42ff9410629fa344be97494ffdbe453a7943f65
