Update comment in modulepreload web platform test

Bug: 740886
Change-Id: I7cdfd6099a24bd36ccb1f962317f83b5e5299f20
Reviewed-on: https://chromium-review.googlesource.com/828342
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524645}
1 file changed