Patch for JDK-8243489 Thread CPU Load event may contain wrong data for CPU time under certain conditions

[Nikolay Martynov]

Hi

It looks like per thread CPU time sent with the CPU load event may be
inadvertently reset under certain conditions (JDK-8243489). This should
address the problem:
http://cr.openjdk.java.net/~jbachorik/8243489/webrev.00/.

Please let me know if any more information is needed.
Thanks!

Nikolay.