[MC] When MCInstPrint::printAnnotation uses a comment stream, it has to ensure
that each comment ends with a newline to match the definition in the header
file.

This is part of <rdar://problem/14687488>.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191787 91177308-0d34-0410-b5e6-96231b3b80d8