ProB-based set element selection for implicit functions defaults to off

[joey-coleman]

Two interpreter tests are failing:

• standard/action/statements/interpretable-implicitfunction.cml
• standard/action/statements/interpretable-implicitfunction2.cml

Both fail because they cannot apply implicit functions that do the simple selection from a set.

I suspect that the interpreter just needs to have ProB enabled for these tests.

[lausdahl]

fixed in 718dcac6e53b110758ab35b62b58c20324dad778