RFR: 8058606 Detailed Native Memory Tracking (NMT) data is not output at VM exit

[George Triantafillou]

Please review this fix for JDK-8058606.  The output from the 
-XX:NativeMemoryTracking=detail option now outputs detailed tracking 
information at VM exit. Previously, only summary tracking information 
was output.

A new test was added to verify the output from both summary and detail 
tracking options.

Bug: https://bugs.openjdk.java.net/browse/JDK-8058606
Webrev: http://cr.openjdk.java.net/~gtriantafill/8058606/webrev/

<http://cr.openjdk.java.net/%7Egtriantafill/8058606/webrev/>The fix was 
tested locally on Linux with jtreg and the JPRT hotspot testset.

-George