In case the v8 revision in chromium was set to an older
revision that's not in the list of recent v8 releases, the
script will bail out too early. This changes iterates over
10 more revisions, which should cover all exceeding revisions
in branch period.

NOTRY=true
TBR=hablich@chromium.org

Review URL: https://codereview.chromium.org/1067793002

Cr-Commit-Position: refs/heads/master@{#27622}