review request -- JDK-801106 Some tests have failed with SIGSEGV on arm-hflt on build b82

[JOSEPH PROVINO]

Make it easy to disable NMT detail in platform specific code.

A new variable NMT_detail_supported is defined and set to true.
It can be disabled in platform specific code as needed.

Webrev is here: http://cr.openjdk.java.net/~jprovino/8011064/webrev/

JDK-8011064 <https://jbs.oracle.com/bugs/browse/JDK-8011064>Some tests 
have failed with SIGSEGV on arm-hflt on build b82 
<https://jbs.oracle.com/bugs/browse/JDK-8011064>