Make run-perf-tests work again with Dromaeo tests.

All tests were just failing because they printed out messages on the console.

The messages are either deprecation warnings (we cannot do much) or a sandbox
warning (bug filed).

R=haraken@chromium.org
BUG=

Review URL: https://codereview.chromium.org/173653002

git-svn-id: svn://svn.chromium.org/blink/trunk@167671 bbb929c8-8fbe-4397-9dbb-9b2b20218538