Mark lib/js/null_test as failing in csp mode

Mark lib/js/null_test as failing in csp mode

I have filed issue 20310 to track this

Committed: https://code.google.com/p/dart/source/detail?r=38827

[ricow1, 2014-08-01 08:55:54]

tbr

[ricow1, 2014-08-01 08:56:05]

Committed patchset #1 manually as r38827 (presubmit successful).

[Bill Hesse, 2014-08-01 09:12:33]

lgtm

[Siggi Cherem (dart-lang), 2014-08-01 17:08:55]

Thanks Rico!