RFR JDK-8165640: Enhance jar tool to allow module-info in versioned directories but not in base in modular multi-release jar files

[Xueming Shen]

Hi,

Please help review the changes for

https://bugs.openjdk.java.net/browse/JDK-8165640
http://cr.openjdk.java.net/~sherman/8146486/webrev

There are two changes
(1) to use the versioned module-info as the module descriptor to validate
the versioned entries, if the root/base "/module-info.class" is missing.
(2) -d to print out all available module-info entries, versioned included.


Thanks,
Sherman