vm_object: don't reset new iterator

[dougm]

Summary

Don't call pctrie_iter_reset on a just-initialized iterator. Let the code jumping back up do the resetting.

[kib]

Is there a way to assert that the iterator is in initial state (I suppose it is trivial to add)? I suggest to assert that in places where the reset was done before the change, so that new 'gotos again' do not miss the reset.

[dougm]

After some goto targets, assert that the iterators have been reset.