RFR 8147491: module graph consistency checks after jlink plugins operate on module pool

[Mandy Chung]

> On Aug 25, 2016, at 7:18 AM, Sundararajan Athijegannathan <sundararajan.athijegannathan at oracle.com> wrote:
> 
> Please review http://cr.openjdk.java.net/~sundar/8147491/webrev.01/ for
> https://bugs.openjdk.java.net/browse/JDK-8147491


I think ResourcePoolConfiguration::validate should simply use all modules in the resource pool as the roots.  ImagePluginStack constructors don’t need to know anything about the input root modules.

Other than that, it looks fine.

Mandy