RFR(xs): 8150843: [windows] os::getTimesSecs() returns negative values for kernel, user times

[Thomas Stüfe]

Hi all,

please review and sponsor this small fix.

It fixes an error in os::getTimesSecs() for windows which causes the
numbers for kernel- and usertime to be off. This does not cause an error,
because the sole user of this function, the TraceCpuTime class, uses this
function to measure twice and calculate the deltas.

I still think it is a good idea to fix this bug - with the fix, the
returned values are based on the process start and will be the same for all
platforms (the *nix platforms use times()).

bug report: https://bugs.openjdk.java.net/browse/JDK-8150843
webrev:
http://cr.openjdk.java.net/~stuefe/webrevs/8150843-windows-osGetTimesSecs/webrev.00/webrev/

Kind Regards, Thomas