hg: jdk/sandbox: 8204565: (spec) Document java.{vm.}?specification.version system properties' relation to $FEATURE

[chris.hegarty at oracle.com]

Changeset: aeb7fb702890
Author:    bchristi
Date:      2018-06-12 14:08 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/aeb7fb702890

8204565: (spec) Document java.{vm.}?specification.version system properties' relation to $FEATURE
Reviewed-by: mchung

! src/java.base/share/classes/java/lang/System.java
! test/hotspot/jtreg/runtime/6981737/Test6981737.java
! test/jdk/java/lang/System/Versions.java