benchmark

8a0f5e36 - add option to run group_fusion

add option to run group_fusion Summary: easily add inductor option to enable `group_fusion` so we can iterate on its implementation Reviewed By: xuzhao9 Differential Revision: D48134482 fbshipit-source-id: a80e0278dc6b9c92e6b0052a75ebc8261d6e1188