memory contexts. Currently, only leaks in expressions executed as
quals or projections are handled. Clean up some old dead cruft in
executor while at it --- unused fields in state nodes, that sort of thing.
Ensure that outer tuple link needed for inner indexscan qual evaluation
gets set in the EvalPlanQual case. This stops coredump, but we still
have resource leaks due to failure to clean up EvalPlanQual properly...