[pytorch] blas gemm fix for k=0 (#33819)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33819
These conditions are for the specific implementation, the fallback implementation works without these checks. So use that if any of these checks isn't true.
Resubmit of https://github.com/pytorch/pytorch/pull/33419 (which got reverted due to a problem with XLA, but which now has been fixed)
ghstack-source-id: 99333280
Test Plan: Test included
Differential Revision: D20121460
fbshipit-source-id: c1056b8e26751e24078bbe80c7cb4b223bcca7cb
