* module/language/cps/slot-allocation.scm (allocate-slots): Don't
allocate slots to unused results of function calls. This can allow us
to avoid consing a rest list for call-with-values with an ignored rest
parameter, and can improve the parallel move code.
* module/language/cps/compile-bytecode.scm (compile-fun): Adapt to avoid
emitting bind-rest in values context if the rest arg is unused.