Migrate does not include transitive frameworkAssemblies

[NTaylorMullen]

Including transitive frameworkAssemblies may make a migrated csproj unmanageable due to how many framework assemblies may need to be included; however, without it users projects may successfully migrate but then fail to build.

Note, once this is fixed this issue should go away; however, that's not slated until after RC. We've worked around this already for migrated project references but have not done it for frameworkAssemblies.

Steps to reproduce

• Unzip FrameworkAssemblyRepro.zip
• dotnet migrate

Expected behavior

• Project1 has a reference node for System.ComponentModel.DataAnnotations.

Actual behavior

• No reference node for System.ComponentModel.DataAnnotations.

Environment data

dotnet --info output:

.NET Command Line Tools (1.0.0-preview3-004007)

Product Information:
 Version:            1.0.0-preview3-004007
 Commit SHA-1 hash:  80ec02b4da

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.14393
 OS Platform: Windows
 RID:         win10-x64

/cc @DamianEdwards @livarcocc