test #7820

test #7820

There was an apparent improvement in the distill params
methodology used in exec_driver_sql which allows raw tuples to
pass through.  In 1.4 there seems to be a _distill_cursor_params()
function that says it can handle this kind of parameter, but it isn't
used and when I tried to substitute it in for exec_driver_sql(),
things still fail.

In any case, add coverage here for the use case of passing
direct tuple params to exec_driver_sql including as the first
param, to note that it isn't mis-interpreted the way it is
in 1.x.

Change-Id: I27b875c0f874aee3f6f0d3e28c4c858dd39344e9