Assertion `n < width` fails in `Bitmap<64>::bit_mask()` during temporary key generation

## Affected version - MariaDB `11.8.8-MariaDB-debug` - Source revision: `46a8eb42a520193686d9a16d4cea4b3e002917e4` ## Summary The server aborts with a debug assertion while optimizing a SELECT over nested views and derived tables with multiple `NATURAL JOIN`s. The failing assertion is: ```text mariadbd: /home/mysql/mariadb/sql/sql_bitmap.h:77: ulonglong Bitmap<64>::bit_mask(uint) const [width = 64]: Assertion `n < width' failed. ``` The stack goes through temporary key construction: ```text TABLE::add_tmp_key(unsigned int, unsigned int, unsigned int (*)(unsigned char*), unsigned char*, bool) sort_and_filter_keyuse(...) make_join_statistics(...) JOIN::optimize_inner() JOIN::optimize() mysql_select() ``` This suggests that optimizer temporary-key generation receives an out-of-range field/key part index after view/derived-table expansion. ## Steps to reproduce Run the following SQL against a debug build: ```sql SET GLOBAL TRANSACTION READ WRITE; SET SESSION TRANSACTION READ WRITE; DROP DATABASE IF EXISTS test_sqlright1; CREATE DATABASE IF NOT EXISTS test_sqlright1; USE test_sqlright1; CREATE TABLE v1099(c1100 INT); CREATE TABLE v0 (   v1 TEXT NOT NULL CHECK (v1 IN ('x', 'x', v6 ^ v6)),   v2 INT,   v3 INT,   v4 INT,   v5 TEXT,   v6 INT ); CREATE VIEW v10 AS SELECT * FROM (   SELECT *   FROM v0   GROUP BY 11433428.000000 + -1 ) AS v8 NATURAL JOIN v0 AS v9 NATURAL JOIN v0 AS v7 WHERE v6 NOT IN (21) AND v6 NOT IN (55); CREATE VIEW v16 AS SELECT v6 FROM (   SELECT *   FROM v0 AS v15   NATURAL JOIN v10   GROUP BY v1   HAVING v3 = v3 ) AS v11 NATURAL JOIN v10 AS v12 NATURAL JOIN v10 AS v13 NATURAL JOIN v10 AS v14 NATURAL JOIN v10 WHERE 'x' = v4 ORDER BY v3, v2 DESC, v2 ASC; SELECT 34672723.000000 FROM (   SELECT 127 + v2 AS v24   FROM v16 AS v25   NATURAL JOIN v0 AS v22   NATURAL JOIN v16 AS v23   NATURAL JOIN v16 ) AS v17 JOIN v10 AS v18 NATURAL JOIN v16 AS v19, v0 AS v20, v16 AS v21 JOIN v10; ``` ## Actual result The server aborts: ```text Assertion `n < width' failed. got signal 6 TABLE::add_tmp_key(...) sort_and_filter_keyuse(...) make_join_statistics(...) Query: SELECT 34672723.000000 FROM ... ``` After replay: ```text server_ready 1 client_rc 0 server_alive_after 0 ```