ubsan build for wdt
ubsan build for wdt

Summary: ubsan build for wdt + optimize the wdt_gen_files build even in dbg mode. use a new wdt_gen_files_prof target for normal build + profiler

Reviewed By: uddipta

Differential Revision: D3276950

fbshipit-source-id: d6684b2d1719f5f2283afa5b53493a24375943da

ldemailly/wdt,luluandleilei/wdt,luluandleilei/wdt,luluandleilei/wdt,ldemailly/wdt,ldemailly/wdt,ldemailly/wdt,luluandleilei/wdt