GitLab

Now in load_tests we change benchmarks base classes that could
unexepectadly affect others tests.
So set pageset_repeat=1 only for SinglePageBenchmark.

Change-Id: Ib0a06ed927d7eb9304856c45f51028d051fb1fc9
Reviewed-on: https://chromium-review.googlesource.com/c/1489192Reviewed-by: Emily Hanley <eyaich@chromium.org>
Commit-Queue: Alexander Yashkin <a-v-y@yandex-team.ru>
Cr-Commit-Position: refs/heads/master@{#636788}