Add missing raw_ostream include

Prior to r259115 this was coming via LTOModule.h and MCContext.h.

Apparently this target is not built by 'check'. =(

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259124 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed