Moving operator << into sparta namespace
Moving operator << into sparta namespace

Summary: This allows us using it in the next diff up the stack as part of a product domain.

Reviewed By: amnn

Differential Revision: D33069785

fbshipit-source-id: 97857df6a739e73f566da1d4a2369ffe4b966632

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex