This adds extra tests for the error message generated for partition
tuple routing in the executor, using more than three levels of
partitioning including partitioned tables with no partitions.  These
tests have been added to fix CVE-2019-10129 on REL_11_STABLE.  HEAD has
no active bugs in this area, but it lacked coverage.

Author: Michael Paquier
Reviewed-by: Noah Misch
Security: CVE-2019-10129