JDBC: investigate usage of test-framework to completely decouple the codebase from the server

[costin]

With the completion of #82077, the JDBC dependencies and driver do not depend on the ES code base allowing different compiler source/targets. However testing wise , the testing framework and its utilities are still being used which keeps the coupling in place - ideally the testing follow the same semantic and environments as the code base itself. Potential things to investigate on this front are:

• replace the usage of testing framework outside sql-action / cli (can we centralize things into a different project?)
• use the testing framework for ES 7.x which is still java 8 enable

[elasticmachine]

Pinging @elastic/es-ql (Team:QL)

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)