PL/pgSQL: Add statement ID to statement structures
This can be used by a profiler as the index for an array of
per-statement metrics.
Author: Pavel Stehule <pavel.stehule@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/CAFj8pRDRCjN6rpM9ZccU7Ta_afsNX7mg9=n34F+r445Nt9v2tA@mail.gmail.com/