adjust shape inference in sls tests (#44936)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44936
need to provide max sequence size and max element size instead of
total
added a check that onnxifi was succesful
Test Plan: sls tests
Reviewed By: yinghai
Differential Revision: D23779437
fbshipit-source-id: 5048d6536ca00f0a3b0b057c4e2cf6584b1329d6
