unique_ptrify MatchableInfo(const CodeGenInstAlias *Alias)'s parameter

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224733 91177308-0d34-0410-b5e6-96231b3b80d8
Use iterators rather than indices to make this forwards-compatible with a change to the underlying container (to std::list)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224734 91177308-0d34-0410-b5e6-96231b3b80d8