Make `dvc pull --run-cache` allow `targets` for a granular pull process

Right now, if I do 

`dvc pull [target]`
this will pull *only* the `target` I am interested in.

However, if I do `dvc pull --run-cache [targets]`
the `target` is ignored, *everything* is pulled from remote. Not even a warning is thrown that `--run-cache` does not accept granularly pulling files.


This is based on https://discuss.dvc.org/t/dvc-pull-run-cache-target/444 discussion