Review Request for 8081347: Add @modules to jdk_core tests

[Mandy Chung]

jtreg supports a new @modules to specify the module and the internal API that a test depends on.  This is to prepare when the module boundaries are enforced at runtime.  This initial patch is contributed by several of us including Alexander Kulyakhtin and Alan.

Webrev at:
   http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8081347/webrev.00/

Thanks
Mandy