Revert "Refer to Control.Concurrent instead of GHC.Conc"
Revert "Refer to Control.Concurrent instead of GHC.Conc"

This reverts commit 6a217ed6f10d440902eb166d2e0ab4127eb3f699.

ilyasergey/GHC-XAppFix,ilyasergey/GHC-XAppFix,ilyasergey/GHC-XAppFix,ilyasergey/GHC-XAppFix