Stop supporting JAVA_VERSION in testing

[llxia]

Currently, we are supporting both JAVA_VERSION and JDK_VERSION as the parameter in the test Jenkins script and TKG. Initially, this was a temporary approach, as our ultimate goal is to completely switch to use JDK_VERSION. We should not keep maintaining the temporary code for JAVA_VERSION to JDK_VERSION mapping (eclipse-openj9/openj9#4645).

This issue is to remove supporting JAVA_VERSION completely.

ToDos:

• Jenkinsfilebase needs to update to make sure JDK_VERSION works
• Update test jobs and grinders to set JDK_VERSION in job configure and remove JAVA_VERSION (depends how the test job is invoked, this may not be a blocker)
• Request upstream jobs to pass in JDK_VERSION if needed
• Remove temporary code for JAVA_VERSION to JDK_VERSION mapping in Jenkinsfile and TKG
• Update docs/wiki/readme accordingly

[llxia]

If auto detects JDK_VERSION, JDK_IMPL and SPEC are completed eclipse-openj9/openj9#442, then JDK_VERSION and JDK_IMPL are not needed in the regular test builds. However, Jenkinsfilebase still needs to be updated to accept JDK_VERSION. If the user chooses nightly in Grinder, JDK_VERSION and JDK_IMPL are still needed.

[keithc-ca]

Shall we assume the references to JAVA_VESION are just typos that should say JAVA_VERSION?

[llxia]

yes, description is updated. Thanks

[AdamBrousseau]

Can this be blocked on #837? Otherwise I (we) will have to manually update a few hundred Jenkins jobs.
OpenJ9 pipelines do not pass JAVA_VERSION or JDK_VERSION, although they could, and if test pipelines ignore the former as the jobs set it by default.

[llxia]

I do not think this is necessarily blocked by #837. Although #837 is a good idea, I also would like to investigate if we could generate the job dynamically.

As you mentioned, upstream jobs could pass JDK_VERSION into test jobs. At the moment, the test script will check for JAVA_VERSION only if JDK_VERSION is not set. That is, if JDK_VERSION is passed in, we will take JDK_VERSION regardless JAVA_VERSION exists or not.
btw, with the completion of eclipse-openj9/openj9#442, test job does not need JDK_VERSION to be set.

[llxia]

Close this as it is a dup of #563