Support noreferrer for window.open()


Tests: https://github.com/web-platform-tests/wpt/pull/15352.

Fixes #4111.
commita9a7944f20ec9223c252578db3e8bf870bca5718
parentf47773d25a7b1a3a03c1047bbc4037d08639cf9b
gita9a7944f20ec9223c252578db3e8bf870bca5718
authorAnne van Kesteren <annevk@annevk.nl>
committerAnne van Kesteren <annevk@annevk.nl>
commit timeTue, 12 Feb 2019 13:54:42 +0100