Until this CL, the Memory benchmark was the only one to be based on a
cctest runner; all others use d8. Besides being a tedious exception to
the rule, this caused issues such as described in the linked bug
(summary: refbuilds are built with v8_static_library, and neither
cctests nor unittests support this configuration).

Here, we move the Memory benchmark into a d8 runner.

Bug: v8:9189, chromium:957029
Change-Id: I9b45ff36f4842cb0bdef2c1c4b0184c5509d3385
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1588464
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61245}