These tests perform GC manually which does not work well with concurrent
marking and stress incremental marking flags.

BUG=chromium:694255

Change-Id: I43e32957bf37053e0d3af07afa00b8bb40935ebd
Reviewed-on: https://chromium-review.googlesource.com/596887Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47070}