RFR 8144355: JDK 9 changes to ZipFileSystem to support multi-release jar files

[Steve Drach]

>>> The changes to ZipFileSystem* looks okay although I wonder if getEntry0 should be renamed to getEntry as it's cleaner when overridden in JarFileSystem.
>> 
>> I did not change this.  I’d like Sherman to comment on it.  I assume getEntry0 was named for a reason.
> It was a private method and originally wrapped with getEntry that has since been removed.

Yes, I changed it to getEntry after Sherman agreed that it should be done.

>> Consistent with ZipFileSystem?  As for long lines, the longest line is 109 characters.  I always try to keep lines shorter than 120 characters.  I think it’s easier to read on a single line.  Seems like a matter of style.
> Best to keep it consistent with ZipFileSystem code. Also it makes it easier when doing side-by-side diffs.

I’ll look at it again, but it does just seem like a personal taste kind of thing.

> 
> 
>> I don’t see what the issue is with the copyright.
>> 
> Tests should have the GPL header, this one has the Classpath exception so I assume it must have been copied from a file in the src tree.

Oh.  Okay, I’ll fix that.