Adjust suffix to "-unittest" like everywhere else in V8.

Accept clang-format suggested changes.

Bug: chromium:1056170
Change-Id: I54c1396e79aff87c052233853d7fe560337eeecf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2190410
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67672}