Remove duplicated comment.

Found by -Wdocumentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182402 91177308-0d34-0410-b5e6-96231b3b80d8
Use std::list so that we have a stable iterator.

I will try to avoid creating these std::strings, but for now this gets
the tests passing with libc++.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182405 91177308-0d34-0410-b5e6-96231b3b80d8