BUG #17570: Unrecognized node type for query with statistics on expressions

The following bug has been logged on the website:

Bug reference: 17570
Logged by: Alexander Kozhemyakin
Email address: a(dot)kozhemyakin(at)postgrespro(dot)ru
PostgreSQL version: 14.4
Operating system: ubunu 20.04
Description:

When executing the following script:
CREATE TABLE t(a INT, b VARCHAR);
INSERT INTO t(a, b) SELECT i, i FROM generate_series(1,100) s(i);
CREATE STATISTICS t_stats (mcv) ON (a), (b) FROM t;
ANALYZE t;
CREATE ROLE u;
--GRANT SELECT ON t TO u;
SET SESSION AUTHORIZATION u;
SELECT * FROM t WHERE a = 1 AND b::int = 1;

I get:
ERROR: unrecognized node type: 1697192808

And it fails with error "permission denied for table t" when condition is
just "a = 1" or "b::int = 1".

The same query executed successfully, if the select permission is granted to
user.
The first bad commit is a4d75c86b