pg_stat_statements stores WITH HOLD cursor query with literals

Hi,

On PostgreSQL 19beta1, pg_stat_statements can store the query of a
WITH HOLD cursor as a separate top-level entry, without normalizing
its constants.

Repro (shared_preload_libraries = 'pg_stat_statements'):

CREATE EXTENSION pg_stat_statements;
LOAD 'auto_explain';
SET auto_explain.log_min_duration = 0;
SELECT pg_stat_statements_reset();
DECLARE c CURSOR WITH HOLD FOR SELECT 1;
CLOSE c;
SELECT toplevel, calls, query FROM pg_stat_statements
WHERE query LIKE 'DECLARE%';

toplevel | calls | query
----------+-------+------------------------------------------
t | 1 | DECLARE c CURSOR WITH HOLD FOR SELECT $1
t | 1 | DECLARE c CURSOR WITH HOLD FOR SELECT 1;
Without auto_explain, only the first row appears. Without auto_explain
but with pg_stat_statements.track = 'all', the second row appears too.

The cursor's query starts inside DECLARE (nesting level 1), but a
WITH HOLD cursor finishes it at commit (nesting level 0).
pgss_ExecutorEnd stores any query that has a queryId and query_instr,
even when pg_stat_statements did not request query_instr itself or
requested it at another nesting level. It then finds no normalized
entry, so it stores the raw text.

Thanks,
Gaurav Singh