make sure CBD test graphs are valid
make sure CBD test graphs are valid

The graphs used for the CBD tests wouldn't validate because they skipped
adding the root module node. Re add the root module transformer and
transitive reduction transformer to the build steps, and match the new
reduced output in the test fixtures.

hashicorp/terraform,rnaveiras/terraform,hashicorp/terraform,tommynsong/terraform,tommynsong/terraform,hashicorp/terraform,rnaveiras/terraform,rnaveiras/terraform,tommynsong/terraform