Revert "Fix the build broken by r189315." and "Move everything depending on Object/MachOFormat.h over to Support/MachO.h."

This reverts commits r189319 and r189315. r189315 broke some tests on what I
believe are big-endian platforms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189321 91177308-0d34-0410-b5e6-96231b3b80d8