RFR: 8156499 Update jlink to support creating images with modules that are packaged as multi-release JARs

[Steve Drach]

Hi,

Please review this changset that makes jlink multi-release jar aware.

issue: https://bugs.openjdk.java.net/browse/JDK-8156499 
<https://bugs.openjdk.java.net/browse/JDK-8156499>
webrev: http://cr.openjdk.java.net/~sdrach/8156499/webrev.00/index.html 
<http://cr.openjdk.java.net/~sdrach/8156499/webrev.00/index.html>

Thanks
Steve