BUG: non-unique indexers with a list-like now return in the same order as the passed values
BUG: handle missing indexers in duplicate indices similary to how unique handles (e.g. by reindexing)
Merge pull request #3563 from jreback/GH3561

BUG: (GH3561) non-unique indexers with a list-like now return in the same order as the passed values