Ensure JDKs are correctly installed

What does this MR do?

Queries asdf for installed Java versions, and executes java -version for each installation. The script will exit if the version cannot be printed. This will hopefully prevent future instances of this: !160 (comment 1251656105)

No user-facing changes so I haven't added a changelog entry.

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template (also in CE)
  • Job definition example
  • CI Templates (to be removed)
  • Vendored CI Templates (also in CE)
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer