Looks like we never ran test262-es6 on mac. After merging
into test262 we've got these failures. Skipping for now.

BUG=v8:4437
LOG=n
NOTRY=true
NOTREECHECKS=true
TBR=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1372603002

Cr-Commit-Position: refs/heads/master@{#30937}