Revert "Add classof implementations to the raw_ostream classes."
Revert "Use the cast machinery to remove dummy uses of formatted_raw_ostream."
The underlying issue can be fixed without classof.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234495 91177308-0d34-0410-b5e6-96231b3b80d8