Instead, use std::sort and std::stable_sort at the 3 (!) call sites
directly. This also removes the weird comparer adaptors from Vector,
which are only used in ZoneList.

R=jkummerow@chromium.org

Bug: v8:9183
Change-Id: I4d0377976fb0a965cb68a21d4307df9ba09fd55d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1587394Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61109}