DERBY-6612 Add code to harness tests to allow running under JDK9 VMs.

Patch derby-run-with-java19 adds the expected harness class fort JDK1.9.
    


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1602266 13f79535-47bb-0310-9956-ffa450edef68