Update tests to work with new behavior.

Thanks Yang Guo for fixing the GC problem in
ad126d46

R=adamk@chromium.org, machenbach@chromium.org
Q_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Bug: v8:4958
Change-Id: Ia7d9417f80087fb6df4ef877d0b4357875ee6c30
Reviewed-on: https://chromium-review.googlesource.com/834458Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Josh Wolfe <jwolfe@igalia.com>
Cr-Commit-Position: refs/heads/master@{#50486}