Bugfix: Resolve bug preventing use of Java 11

What does this MR do?

• Fixes a bug that was introduced by Simplify .tool-versions conflict handling (!213 - merged) • Adam Cohen • 17.5 which prevented switching to Java 11 if SAST_JAVA_VERSION: 11 was configured.
• Adds explicit integration tests to ensure that switching to Java 11 and 17 works as expected.

What are the relevant issue numbers?

N/A

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 updated/added for this feature/bug
• Job definition updated, if necessary
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• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer