RFR - 8132734: java.util.jar.* changes to support multi-release jar files

[Steve Drach]

>> Let’s try again, this time there are tests.  Please review the following webrev that adds support for multi-release jars as specified in JEP-238.
> Good to have tests this time :-)
> 
> I see several JAR files in the webrev, shouldn't the tests create these so that we don't have to check in binary files? I realize the signed case might be a bit of work but there may be some security tests that could provide examples.

The current test directory contains binary jar files. In fact in all the test directories, there are 52 binary .jar files. I added three more.  I thought about generating the jar files but the problem I run into is that there are two test classes that use the same files and creating the files twice seemed to be a bit wasteful.  I couldn’t figure out a reliable way to have one test class create the files and the other one just use the files.