<AWT Dev> [9] Review request: 8041490 PIT: [macosx] Crash in system tray functionality check test

[Petr Pchelko]

Hello, AWT Team.

Please review the fix for the issue:
https://bugs.openjdk.java.net/browse/JDK-8041490
The fix is available at:
http://cr.openjdk.java.net/~pchelko/9/8041490/webrev/

After Toolkit.sync() was implemented on OS X we've found a bug which was unnoticed: 
when the WarningWindow is disposed it's surface is not invalidated.
So if we attempt to flush the GL queue after that we would crash.
I've added the loop in the test to increase the probability of the crash.

With best regards. Petr.