Per bug 1322570 comment 46, it's not easy to replace ComputedJustifyItems()
and UsedJustifySelf()'s internal nsStyleContext::GetParent() without
correctness penalty, so we use GetParentAllowServo() for now.
Also, fix the reftest.list added in bug 1334403 which incorrectly wrote test
page as reference page.
MozReview-Commit-ID: 6kAAWSFojd5