Convert ScriptErrors to DeviceFailures in run-webkit-tests --android.

TBR=peter@chromium.org
BUG=305040

Review URL: https://codereview.chromium.org/77413002

git-svn-id: svn://svn.chromium.org/blink/trunk@162324 bbb929c8-8fbe-4397-9dbb-9b2b20218538