[Algorithm] Add make_const_ref corresponding to make_const_ptr

Reviewers: aaron.ballman

Subscribers: dexonsmith, kristina, llvm-commits

Differential Revision: https://reviews.llvm.org/D56622

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351009 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed