RootCanal: Decouple TestModel from {LinkLayer,Hci}SocketDevice

Instead of constructing the {LinkLayer,Hci}SocketDevice
inside the test model take it as a parameter and expose it
to the TestModel caller to be able to give subclasses to
the testmodel

This also remove the hard dependency of socket
for the TestModel

Test: gd/cert/run
Change-Id: Ia516a41463174baf186e0c3c4fe4da04393756cc