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

[Steve Drach]

>>>> Er, I thought the plan was for the set of concealed packages to be the same. It's okay for the ConcealedPackages in the base section to include "empty" packages.
>>> 
>>> I wasn’t involved with that decision.  Chris wrote that code, perhaps he can comment.
>> 
>> This surprises me, as I have the same recollection as Alan; no additional
>> concealed packages are allowable in the versioned section.
>> 
>> I just checked the jar tool, and it does NOT add any versioned specific
>> concealed packages.
> 
> 
> If a JAR file contains an empty directory, should `q` be considered as a concealed package in the base section?
> 
> $ jar -t --file hi.jar
> META-INF/
> META-INF/MANIFEST.MF
> module-info.class
> p/Hi.class
> q/
> 
> currently not:
> 
> $ jar -d --file mr.jar
> hi
>  requires mandated java.base
>  conceals p

Is a jar tool that takes a -d option lurking somewhere?  The latest one I have does not have that option.