RFR 8071487: javax/management/monitor/GaugeMonitorDeadlockTest.java timed out

[Jaroslav Bachorik]

Please, review the following test change

Issue : https://bugs.openjdk.java.net/browse/JDK-8071487
Webrev: http://cr.openjdk.java.net/~jbachorik/8071487/webrev.00

GaugeMonitorDeadlockTest fails intermittently due data race - the call 
to monitorProxy.start() on L105 will eventually result in incrementing 
the GetCount attribute. If that happens before L109 had the chance to 
run the loop on L113-128 will become infinite. The initial value will 
contain the already incremented GetCount value and GetCount attribute 
value will not get further incremented.

I took the liberty to fix the same issue in 
test/javax/management/monitor/StringMonitorDeadlockTest.java, not 
waiting for the real test failure.

Thanks,

-JB-