Wrong progress report for operations on InnoDB tables

Initially reported on the mailing list: https://lists.launchpad.net/maria-discuss/msg02495.html .

Stage: 1 of 72 'altering table' 350% of stage done. 

Reproducible as described.

Dataset: salaries table in the employees sample database.

Statements that exhibit the incorrect behaviour:

ALTER TABLE salaries ENGINE = Innodb;

ALTER TABLE salaries ADD id INT NULL;

ALTER TABLE salaries DROP id;

ALTER TABLE salaries ROW_FORMAT = COMPRESSED;

I also saw the mentioned 350% and some other values, e.g.

MariaDB [employees]> ALTER TABLE salaries ADD id INT NULL;

Stage: 1 of 85 'altering table'    200% of stage done

MyISAM looks reasonable (2 stages, below 100% progress).

Not reproducible on 5.5.
10.0 has a different problem – progress for InnoDB tables is not reported at all.