This CL adds sort benchmarks for BigUint64Array and BigInt64Array.
They form their own benchmark group separate from the Int and
Float types/element kinds.

R=jgruber@chromium.org

Bug: v8:7382
Change-Id: Id3ce125be36a42c419a2632edc5f930547a1720e
Reviewed-on: https://chromium-review.googlesource.com/1016643Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#52668}