RFR(M/L, Windows): 8245042: Improve scalability of reading Windows Performance counters via PDH when using the Process object

[Markus Gronlund]

Greetings,

Kindly asking for review of the following enhancement / bug fix:

Enh. / bug: https://bugs.openjdk.java.net/browse/JDK-8245042 
Webrev: http://cr.openjdk.java.net/~mgronlun/8245042/webrev01/ 

The Jira issue contains a (very) long problem description.

Thanks in advance
Markus