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

[Steve Drach]

Hi,

Please review the latest webrev for this issue.

issue: https://bugs.openjdk.java.net/browse/JDK-8156499 <https://bugs.openjdk.java.net/browse/JDK-8156499>
webrev: http://cr.openjdk.java.net/~sdrach/8156499/webrev.03/ <http://cr.openjdk.java.net/~sdrach/8156499/webrev.03/>

I believe this changeset resolves all the issues Alan and Mandy had with the previous changesets.  They are:

1. the test silently passes if java.base.jmod can not be found on the module-path
2. the test assures that
    a. the correct module-info class is in the module image
    b. the correct resource file is in the module image
    c. the correct class file is in the module image
3. As before, the image module created is for the Runtime.Version of jlink.  This demonstrates that MMR jar files
    are handled correctly, but will have to be updated to create an image based on the Runtime.Version of java.base
    when the appropriate code is migrated from jake.

Thanks,
Steve