Use the cast machinery to remove dummy uses of formatted_raw_ostream.

Use the cast machinery to remove dummy uses of formatted_raw_ostream.

If we know we are producing an object, we don't need to wrap the stream
in a formatted_raw_ostream anymore.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234461 91177308-0d34-0410-b5e6-96231b3b80d8