Refine exclude files logic

New exclude files (for openjdk, functional, etc) have to be created for the new JDK version regardless of whether we have any new changes. See https://github.com/eclipse-openj9/openj9/issues/17901.

I think we should have a common exclude file. A new exclude file only needs to be created if there are any specific excludes for particular JDK version.

Start by reading the linked OpenJ9 issue 17901, then trace how exclude files for OpenJDK and functional tests are created in aqa-tests. Done means the existing exclude logic uses a common file where possible and creates a JDK-version-specific file only when that version has specific excludes.

Written by the indexing model from the issue text.