RFR (S): JDK-8020829: JT_HS: 2 runtime NMT tests fail on platforms if NMT detail is not supported

[Chris Plummer]

https://jbs.oracle.com/bugs/browse/JDK-8020829
http://cr.openjdk.java.net/~cjplummer/8020829/webrev-03/

On some platforms, NMT detail is not supported, and this was causing 
some jtreg tests to fail. These tests now query a new WhiteBox API to 
see if NMT detail is supported, and now behave properly if it is not 
supported.

I also fixed #ifdef INCLUDE_NMT in whitebox.cpp that should instead be 
#if INCLUDE_NMT. The source within the #if is now properly excluded from 
minimal VM builds.

The addition of Platform.isArm() is to support changes in closed source.

Testing was done using the existing NMT tests, verifying that they now 
pass on platforms where NMT detail is not supported, and still pass on 
platforms where NMT detail is supported. A jprt job is currently in the 
queue to run all NMT jtreg tests on all platforms supported by jprt.

Thanks!

Chris Plummer