RFR: 8242786: [macos] tools/jpackage/share/IconTest.java fails: ABORT trying to dequeue work

[alexander.matveev at oracle.com]

Please review the jpackage fix for bug [1] at [2].

- Detach fails sometimes due to disk image being busy. Not sure what 
keeps disk image busy. Probably antivirus or something else. Within 
short period of time disk image can be detach. So, fix is just re-try 
detach if it did not work right away. With proposed fix I was not able 
to reproduce this issue again.

[1] https://bugs.openjdk.java.net/browse/JDK-8242786

[2] http://cr.openjdk.java.net/~almatvee/8242786/webrev.00/

Thanks,
Alexander