Do not print seed in MallocDebug
Do not print seed in MallocDebug

Summary: Add a compile-time option to print, but do not print by default. MallocDebug is thread-local and redex spawns too many threads for this to not just be noise.

Reviewed By: minjang

Differential Revision: D19581013

fbshipit-source-id: da777ef2851d4f61670f735b56197ea0b0140d9d

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