Turn off scalar_check for mode; the underlying code is correct.
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/29948
Test Plan: Imported from OSS
Differential Revision: D18548053
Pulled By: gchanan
fbshipit-source-id: 15cdfc24d3e5123497c72dc09c5e6b28cb5e1f88
