Adds unit tests for testing runtime client against Teiid 8.5

* Includes fixes for failing unit tests

* Refactoring of unit test hierarchies to allow for extending and
  overriding 8 tests with 8.5

* Fixes warnings in unit tests
Adds unit tests for testing runtime client against Teiid 8.6 and 8.7

* Includes fixes for failing unit tests

* Refactoring of unit test hierarchies to allow for extending and
  overriding 8.5 tests with 8.6 and 8.7

* Fixes warnings in unit tests