measure impact of innodb_log_optimize_ddl

Measure the actual performance difference between innodb_log_optimize_ddl=OFF and the default ON, in 10.2, on ALTER TABLE…ADD INDEX…, ALGORITHM=INPLACE or ALTER TABLE…FORCE, ALGORITHM=INPLACE, both for small and big tables, both for small and big buffer pool (with lots of other tables populating the buffer pool).

If the reduced redo logging does not seem to offer much benefit (it does require an extra buffer pool scan & page flush before re-enabling logging), then maybe we could set this option OFF by default