[DF] Remove calls to `gInterpreter->Declare` from a computation graph with no jitted nodes

Even if no RDF node is jitted, each Define declares an alias of the return type of the Define to the interpreter in case jitting will need it.
Logic could be made smarter (at the cost of complexity), so that it only performs those gInterpreter->Declare calls if indeed some jitted node is present that could need the declarations.

For reference, the cost of this jitted declarations seems to be in the ballpark of 1 MB per computation graph.