Drive-by change: Add std::iterator_traits typedefs to ZoneChunkListIterator
so we can use <algorithm>.

R=mstarzinger@chromium.org

Bug: v8:7754
Change-Id: Ib7d1c622fdb761fc99bea373dbdef206f15bd4a0
Reviewed-on: https://chromium-review.googlesource.com/1145075
Commit-Queue: Simon Zünd <szuend@google.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54601}