Include input index in console.log statements

[rkalis]

Right now console.log statements from multiple inputs of the same contract are indistinguishable:

(from test 'should still work with different instances of the same contract, with different paths due to different contract parameter values')

SameNameDifferentPath.cash:5 a is 0
SameNameDifferentPath.cash:8 a is not 0

Could include input index, e.g.:

[Input 0] SameNameDifferentPath.cash:5 a is 0
[Input 1] SameNameDifferentPath.cash:8 a is not 0