Write JS tests to cover all possible cases of mutliplanner + CBR fallback.

When setting planRankerMode = automaticCE then planning should combine both multiplanner and CBR in the following way: There will be an initial round of multiplanning and depending on when that round ends we'll:

1. Stick with the multiplanning results if multiplanner exited hitting EOF.
2. Stick with the multiplanning plan if multiplanner exited due to filling a batch.
3. Let CBR plan the query otherwise. This will currently happen if multiplanning exhausted the allocated maximum works without either hitting EOF or filling a batch.

Assertions should happen at the winning plan level