This CL adds a baseline implementation for Array.p.reverse in Torque,
as well as fastpaths for PACKED elements kinds.

Support for sparse JSArrays was removed.

R=jgruber@chromium.org, petermarshall@chromium.org

Bug: v8:7624
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I12900fbbb44746f1c5d36b78be826e14b88b4f69
Reviewed-on: https://chromium-review.googlesource.com/1185600
Commit-Queue: Simon Zünd <szuend@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55369}