[9] Review request for 8048506: [macosx] javax.swing.PopupFactory issue with null owner

[dmitry markov]

Hello,

Could you review the fix for jdk9, please?
    bug: https://bugs.openjdk.java.net/browse/JDK-8048506
    webrev: http://cr.openjdk.java.net/~dmarkov/8048506/jdk9/webrev.00/

Problem description: this is regression caused by the changes for 
JDK-8042465
Fix: added null check to PopupFactory.getPopup() method to avoid NPE 
when getPopup() is invoked with null-owner argument.

Thanks,
Dmitry