Rebaseline fast/images/imagemap-case.html after r154917

The new results included the two "success" lines, which looks like a better
result than the old ones.

TBR=schenney@chromium.org
BUG=257352

Review URL: https://codereview.chromium.org/20376002

git-svn-id: svn://svn.chromium.org/blink/trunk@154920 bbb929c8-8fbe-4397-9dbb-9b2b20218538