RFR(S): JDK-8079337: Format string issues in workgroup.cpp and taskqueue.cpp

[David Lindholm]

Hi,

Please review this small patch that fixes the few format string issues 
present in workgroup.cpp and taskqueue.cpp.


Webrev: http://cr.openjdk.java.net/~david/JDK-8079337/webrev.00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8079337

Testing: JPRT passed.


Thanks,
David