Fixup RuntimeDependenciesResolver test

[pranavkm]

• Changed the test to be rooted on the standalone app (versus the test which has a different reference graph)
• Use embedded resources which was easier to transfer around and should likely fix the helix issue.

Fixes #12059

[javiercn]

I'm not sure how you are fixing it, I think I understand the problem was we weren't traversing dependencies properly, but I'm not sure how you are fixing it.

I'm signing off because I trust you and I don't see anything wrong with the code/test changes, but in the future it would help if you can share a bit more details about the fix on the change description, as it was not clear to me what was going on.

[pranavkm]

The issue was that we were using the ref assemblies for the test to walk the dependency graph for the standaloneapp. You get different results as a result of this since the test app is netcoreapp vs client which is a netstandard targeting app. Hope that helps.