Avoid imputing liveness to expressions (not just applications) whose outputs are not needed.
Avoid imputing liveness to expressions (not just applications) whose
outputs are not needed.

Unlike intraprocedural-dead-variable-elimination, the improve liveness
map loop does not have the invariant that if you are looking at
something then some output of it is live; and I chose to write
defensively rather than figure out how to enforce that invariant.

axch/dysvunctional-language,axch/dysvunctional-language,axch/dysvunctional-language,axch/dysvunctional-language