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

[Steve Drach]

>>> I’ve put out another webrev, http://cr.openjdk.java.net/~sdrach/8156499/webrev.05/, that addresses Mandy’s concerns.  In particular I demonstrate that the resultant image is “runnable” and that a Main class in the image can/cannot find the java.logging module when the module-info.class is changed to require java.logging in one case but not in the other.
>> 
>> Looks okay in general.  The jlink change looks correct.  Thanks for updating the test.
> 
> In fact - does this test run on windows?
> 
> 239         Path java = Paths.get(image, "bin", "java”);
> 
> On windows, shouldn’t this need to be “java.exe”?

I haven’t run it on jprt yet, but I’ll note that tools/jlink/plugins/SystemModuleDescriptors/UserModuleTest does the same thing (finds java, not java.exe) and has apparently been run on windows many times.  If jprt turns up an error here, I’ll fix it.