Compiles a computation with a single aggregation to
Compilation proceeds by splitting on the lone aggregation, and using the
aggregation's internal functions to generate a semantically equivalent
computation_impl.ConcreteComputation to compile. Assumed
to be representable as a computation with a single aggregation in its
body, so that for example two parallel aggregations are allowed, but
multiple dependent aggregations are disallowed. Additionally assumed to be
of functional type.
A semantically equivalent instance of
comp is not a building block, or is not of functional TFF
comp cannot be represented as a computation with at most
one aggregation in its body.