GELU acc OP (#65957)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65957
added accelerator ops and unit test for GELU.
Test Plan: buck test glow/fb/fx/oss_acc_tracer:test_acc_tracer
Reviewed By: 842974287
Differential Revision: D31277083
fbshipit-source-id: f66dd05ef574db58cfa599e3575f95f1ebe82e93
