Revert "Use unique_ptr to manager FilterChooser ownership."

std::map::emplace isn't working on some of the bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217015 91177308-0d34-0410-b5e6-96231b3b80d8
Recommit "Use unique_ptr to manager FilterChooser ownership."

Just using insert of a pair this time instead of emplace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217018 91177308-0d34-0410-b5e6-96231b3b80d8