RFR of JDK-8211974,move testlibrary/java/util/jar/CreateMultiReleaseTestJars.java to a separate testlibrary

[Hamlin Li]

would you please review the following patch?

bug:

   https://bugs.openjdk.java.net/browse/JDK-8211974

   https://bugs.openjdk.java.net/browse/JDK-8211972

   https://bugs.openjdk.java.net/browse/JDK-8211973

   https://bugs.openjdk.java.net/browse/JDK-8211979

webrev: http://cr.openjdk.java.net/~mli/8211974/webrev.00/

Thank you

-Hamlin