[io] do not reap completions after resubmitting a PartialCompletableFuture
Reaping completions after resubmitting a PartialCompletableFuture
can lead to unbound recursion when the resubmitted Future was
again partially completed during the resubmission.
We already observed a stack overflow due to recursion for this in
the IncrementalCompletionTest
using completer thread with wakeup
behaviour.
Fixes #17 (closed).
Edited by Maxim Onciul