Add testcases for many already fixed bugs.

Closes PR11901.
Closes PR11972.
Closes PR12022.
Closes PR12224.
Closes PR12506.
Closes PR12533.
Closes PR12596.
Closes PR13198.
Closes PR13418.

Already fixed bugs, with existing testcases.
Closes PR12529.
Closes PR12631.
Closes PR13127.
Closes PR13128.
Closes PR12970.
Improve types for exit and in-naturals.
Improve type of make-immutable-hash.

Closes PR13297.
Fixes *-filter types and filter of zero?.

Closes PR13275.