DuckDB considers identifiers with different casing the same even if they are quoted.

The most minimal example of this is the following schema:

CREATE TABLE a(b int);
CREATE TABLE "A"(c int);
INSERT INTO a VALUES(1);

When using postgres execution this correctly outputs:

> SELECT * FROM a, "A" as aa;
 b │ c
───┼───
(0 rows)

But when enabling duckdb execution both a and "A" are interpreted as a. Resulting in the following incorrect result:

> SELECT * FROM a, "A" as aa;
 b │ b
───┼───
 1 │ 1
(1 row)

This happens even when I set preserver_identifier_case to true on the DuckDB connection.