Check for scope if test assign test scope to interdependent projects.

With this that `test-jar` struggle ends. We no longer need to detect that, I somehow "feel" if a project dependency on another project (in multiproject build) has test scope then we should do this. 
No, this won't work correctly because you won't get the compilation artifact, just the test one.  You need:

`test->test;test->compile`.  

Might help if you add a test case which checks the classpath to make sure it does the right thing.