The sort benchmarks are currently in their own directory, because we
might want to run them in isolation during the upcoming sort rework.

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

Bug: v8:7382
Change-Id: Ic2e4e34d2838690529511d591099a66d0b908b0a
Reviewed-on: https://chromium-review.googlesource.com/1004997Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#52537}