RFR : JDK-8151797 - java/lang/management/ThreadMXBean/ThreadLists.java : inconsistent results

[Harsha Wardhana B]

Hello All,

Please review fix for,
Issue : JDK-8151797 <http://JDK-8151797> - 
java/lang/management/ThreadMXBean/ThreadLists.java : inconsistent results
Webrev : http://cr.openjdk.java.net/~hb/8151797/webrev.00/

Root-cause :  call-site cleaner thread not started before counting 
threads via Thread.getAllStackTraces();.
Fix : Create ThreadMXBean at the beginning of test so that call-site 
cleaner thread will be started.

Thanks
Harsha