Update testJobTemplate to accommodate dragonwell & corretto

[smlambert]

We build and test several JDK implementations, so it will be useful to update the testJobTemplate so that it could generate test jobs for all the 'JDK_IMPL' that we support.

Right now, the template uses JDK_IMPL to set JDK_IMPL_SN, which sets the name of the test job that is generated, so those variables should be able to be set to more than just openj9 and hotspot: https://github.com/AdoptOpenJDK/openjdk-tests/blob/master/buildenv/jenkins/testJobTemplate#L90

[smlambert]

Fixed via #2056