RFR: 6543856: MonitorVmStartTerminate.sh fails intermittently

[Erik Gahlin]

Could I please have a review of this intermittently failing test.

Removed Thread.sleep and instead used two count down latches. Also did 
some cleaning up; removed an unused import, added generics etc.

Thanks
Erik

Webrev:
http://cr.openjdk.java.net/~egahlin/6543856_1/

Bug:
https://bugs.openjdk.java.net/browse/JDK-6543856