Fix OSS build by adding missing powermock dependency
Fix OSS build by adding missing powermock dependency

Summary: The previous change was missing a powermock dependency for the `:fbcore:testDebugUnitTest` target

Reviewed By: oprisnik

Differential Revision: D5245533

fbshipit-source-id: 5b8bd083d9c7078559a64e38ec26cf77ef967047

facebook/fresco,xjy2061/NovaImageLoader,MaTriXy/fresco,facebook/fresco,MaTriXy/fresco,xjy2061/NovaImageLoader,facebook/fresco,s1rius/fresco,s1rius/fresco,MaTriXy/fresco,facebook/fresco,MaTriXy/fresco,facebook/fresco,xjy2061/NovaImageLoader,facebook/fresco,xjy2061/NovaImageLoader,MaTriXy/fresco,s1rius/fresco,xjy2061/NovaImageLoader,s1rius/fresco