Potentially remove aliasing of dependencies in CMake

[lockshaw]

Address @elliottslaughter's idea in https://reviewable.io/reviews/flexflow/flexflow-train/1629#-OmOVcMl4gGR8Ink49vR

[elliottslaughter]

If you're willing to wait, most of this is included in my branch here: https://github.com/elliottslaughter/flexflow-train/tree/realm-deploy

(Not yet a PR because it's still stacked on top of other outstanding PRs.)