Fix results_organizer_unittest.py

Now that multiple iters inside a single run all report the correct
pass/fail status, update the unittest to reflect that (is has been
broken now for about a month).

BUG=chromium:723807
TEST=ran unittest with fix and it passes now.

Change-Id: Ie92034bbf073b73ce820f28c238f99192840197f
Reviewed-on: https://chromium-review.googlesource.com/508277


Commit-Ready: Caroline Tice <cmtice@chromium.org>
Tested-by: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>