[BUG] Support LogicalValues which can come out of calcite relational algebra plan

[felipeblazing]

query = """SELECT CASE 
    WHEN exists(SELECT 1 FROM toy_table AS gc1, toy_table AS gc2
        WHERE gc1.name = 'Construction Material/Fixtures'   
            AND gc2.name = 'Cement' 
            AND gc2.path LIKE gc1.path || '%' )
    THEN 'true'
    ELSE 'false'
END
"""

Fails because it outputs a relational algebra step that we don't quite support. The step is

LogicalValues(tuples=[[{ 0 }]])

This should be pretty trivial to implement.