Set SCCACHE_IDLE_TIMEOUT=1200 (#16728)
Summary:
Doubling the sccache timeout from default of 600.
the asan build of #16645 will fail without this change.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16728
Differential Revision: D13963727
Pulled By: li-roy
fbshipit-source-id: 3614d75c1b46d663fa05b84f99d8a099283a8e64
