Without this fix, two rules [PASS, MODIFIER] and [FAIL]
would be joined as [PASS, MODIFIER, FAIL], undermining the
intention of the second rule to mark a test as failing.

BUG=v8:4680,v8:4900

Review-Url: https://codereview.chromium.org/2201033002
Cr-Commit-Position: refs/heads/master@{#38238}