Remove use of deprecated "phantom.args"

JS library test uses phantom.args which is deprecated at least since Oct 29, 2011[1] and removed from PhantomJS 2.

Build log shows that the build system tries to find phantom 1.X but for some reason, in my environment, it uses phantom2 and the test fails.

The failure may only be a configuration problem but removing use of deprecated API would be a good idea.

[1] https://code.google.com/p/phantomjs/issues/detail?id=276