Wrap in IS_FAST_BUILD like similar tests, to avoid flakes

TBR=aboxhall@chromium.org

Bug: 1141280
Change-Id: I4682a0ed73e14bc8243bb57326334d0db752fa4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2518625


Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824899}