[9] Review request for 8081454: [TESTBUG]Some java/awt/Mixing tests fail in OEL 7 only

[Semyon Sadetsky]

Hello,

Please review fix for JDK9:
bug: https://bugs.openjdk.java.net/browse/JDK-8081454

webrev: http://cr.openjdk.java.net/~ssadetsky/8081454/webrev.00/

A number test of issues specific for OEL 7 is fixed. Some of them are 
synchronization issues, some are related to different size of frame 
decoration on Gnome3 (mouse click occasionally falls to the minimize 
button). The rest test failures are addressed by JDK-8178905.

--Semyon