Review request for 7124364: [macosx] Robot screen capturing functionality doesn't work

[Leonid Romanov]

Hi,
Please review a fix for http://monaco.us.oracle.com/detail.jsf?cr=7124364

The fix removes a bunch of code that was only useful when Robot used OpenGL for taking a screenshot. The removed code prevented Robot from correctly taking screenshot in case of multiple monitors configuration. 

webrev: http://cr.openjdk.java.net/~leonidr/7124364/webrev.00/

Thanks,
Leonid.