RFR(xs): 8152180: SIGFPE in CMSCollector::preclean with big CMSScheduleRemarkSamplingRatio

[sangheon]

Hi all,

Could I have a couple of reviews for this tiny change?

There would be an arithmetic overflow with 
CMSScheduleRemarkSamplingRatio at CMSCollector::preclean() as the 
flag(uintx type with max limit of max_uintx) is multiplied by 100.
This change is simply rephrased the calculation routine to avoid the 
overflow and changed the flag's type to 'uint' because 'uintx' seems too 
large for the flag.

CR: https://bugs.openjdk.java.net/browse/JDK-8152180
Webrev: http://cr.openjdk.java.net/~sangheki/8152180/webrev.00
Testing: JPRT, runtime/commandline JTREG for all platforms

Thanks,
Sangheon