RFR(XS) 8237250: pmap and pstack should do a better of making it clear that they are not supported on Mac OS X

[Chris Plummer]

Hello,

Please review the following:

https://bugs.openjdk.java.net/browse/JDK-8237250
http://cr.openjdk.java.net/~cjplummer/8237250/webrev.01/index.html

Details are in the CR.

thanks,

Chris