This CL fixes the UnboundLocalError in unittests testsuite.

R=machenbach@chromium.org

Bug: chromium:1091200
Change-Id: I9a4e032915b2750c28e3eb9f97042b75ca547801
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2232540
Commit-Queue: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Auto-Submit: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68203}