Add sql test suite coverage for query operators

[rampage644]

We need extensive test coverage to properly identify what is working within query operators (intersect, etc)

[camuel]

@andheroe what is the status ?

[andheroe]

https://github.com/Embucket/embucket/tree/39f75d05109adad375322bafc2d4d57cee5a4832/test/sql/sql-reference-commands/Query_operators here are SLTs.