Properly use cudaGetLastError return code. (#18485)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18485
I don't know how (1) we landed the wrong version of the patch and (2) how
this passed the push blocking test
Reviewed By: pjh5
Differential Revision: D14621961
fbshipit-source-id: 0a3953d7adcdc79727a61c2acff65f436dcafe55
