RFR: JDK-82177923: Modular jars in jpackage are not working

[Andy Herrick]

Please review the jpackage fix for bug [1] at [2].

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

JDK-8217793 fixes the use of modular jars

[1] https://bugs.openjdk.java.net/browse/JDK-8217793

[2] http://cr.openjdk.java.net/~herrick/8217793/webrev.01/

/Andy