Suppress test262 test that tests duplicate properties

In ES6 duplicate properties are allowed

BUG=
LOG=Y

Review URL: https://codereview.chromium.org/492793002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23246 ce2b1a6d-e550-0410-aec6-3dcde31c8c00