Remove support for passing data via STDIN

Summary: Ref T7674. Remove support for passing data to linters via STDIN. This functionality exists primarily for pre-receive workflows (which don't have a working copy to act on), but these workflows are going away soon.

Test Plan: arc unit

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7674

Differential Revision: https://secure.phabricator.com/D12696