RFR 8242430: Correct links in javadoc of OperatingSystemMXBean

[Daniil Titov]

Please review a javadoc fix [1] that corrects the links in the description of  getTotalPhysicalMemorySize() 
method in com.sun.management. OperatingSystemMXBean class. The CSR [2] needs a reviewer as well.

[1] Webrev:  http://cr.openjdk.java.net/~dtitov/8242430/webrev.01/ 
[2] CSR: https://bugs.openjdk.java.net/browse/JDK-8242431 
[3] Bug: https://bugs.openjdk.java.net/browse/JDK-8242430 

Thank you,
Daniil