fix Android test expectations for fast/iamges/png-suite/test.html

TBR=jsbell@chromium.org
BUG=303648

Review URL: https://codereview.chromium.org/35763005

git-svn-id: svn://svn.chromium.org/blink/trunk@160251 bbb929c8-8fbe-4397-9dbb-9b2b20218538